diff --git a/full/Changes b/full/Changes
index 8147bcc..0ceb78d 100644
--- a/full/Changes
+++ b/full/Changes
@@ -9,7 +9,8 @@
 - Made scope param required in authorization request (solved #508)
 2023-01-31
 - Allowed OAuth2 clients to use localhost as redirect URIs.
-
+2023-02-03
+- Fixed content-type in error responses by changing it to application/json
 
 # version 0.69.1
 
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2AdminController.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2AdminController.java
index 1ab9d06..9027071 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2AdminController.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2AdminController.java
@@ -5,6 +5,7 @@
 import javax.ws.rs.GET;
 import javax.ws.rs.POST;
 import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
 import javax.ws.rs.core.Context;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
@@ -27,6 +28,7 @@
 @Controller
 @Path("{version}/oauth2/admin")
 @ResourceFilters({ APIVersionFilter.class, AdminFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class OAuth2AdminController {
 
     @Autowired
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2Controller.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2Controller.java
index 0efcbbe..f7df50b 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2Controller.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuth2Controller.java
@@ -62,6 +62,7 @@
 @Controller
 @Path("{version}/oauth2")
 @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class, BlockingFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class OAuth2Controller {
 
     @Autowired
@@ -238,7 +239,6 @@
     @Path("token")
     @ResourceFilters({APIVersionFilter.class})
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public Response requestAccessToken (@Context HttpServletRequest request,
             @FormParam("grant_type") String grantType,
             MultivaluedMap<String, String> form) {
@@ -391,7 +391,6 @@
     @POST
     @Path("token/list")
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<OAuth2TokenDto> listUserToken (
             @Context SecurityContext context,
             @FormParam("super_client_id") String superClientId,
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuthClientController.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuthClientController.java
index 7ec4758..ae27c80 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuthClientController.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/OAuthClientController.java
@@ -5,7 +5,6 @@
 import javax.ws.rs.Consumes;
 import javax.ws.rs.DELETE;
 import javax.ws.rs.FormParam;
-import javax.ws.rs.GET;
 import javax.ws.rs.POST;
 import javax.ws.rs.Path;
 import javax.ws.rs.PathParam;
@@ -58,6 +57,7 @@
 @Path("{version}/oauth2/client")
 @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class,
         BlockingFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class OAuthClientController {
 
     @Autowired
@@ -92,7 +92,6 @@
     @POST
     @Path("register")
     @Consumes(MediaType.APPLICATION_JSON)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public OAuth2ClientDto registerClient (
             @Context SecurityContext securityContext,
             OAuth2ClientJson clientJson) {
@@ -147,7 +146,6 @@
     @POST
     @Path("reset")
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public OAuth2ClientDto resetClientSecret (
             @Context SecurityContext securityContext,
             @FormParam("client_id") String clientId) {
@@ -166,7 +164,6 @@
     @POST
     @Path("{client_id}")
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     @ResourceFilters({ APIVersionFilter.class})
     public OAuth2ClientInfoDto retrieveClientInfo (
             @PathParam("client_id") String clientId,
@@ -203,7 +200,6 @@
     @POST
     @Path("/list")
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<OAuth2ClientInfoDto> listUserClients (
             @Context SecurityContext context,
             @FormParam("super_client_id") String superClientId,
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/PluginController.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/PluginController.java
index d377da3..006698b 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/PluginController.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/PluginController.java
@@ -33,6 +33,7 @@
 @Path("{version}/plugins")
 @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class,
         BlockingFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class PluginController {
 
     @Autowired
@@ -44,7 +45,6 @@
 
     @POST
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<OAuth2ClientInfoDto> listPlugins (
             @Context SecurityContext context,
             @FormParam("super_client_id") String superClientId,
@@ -68,7 +68,6 @@
     @POST
     @Path("/install")
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public InstalledPluginDto installPlugin (
             @Context SecurityContext context,
             @FormParam("super_client_id") String superClientId,
@@ -93,7 +92,6 @@
     @POST
     @Path("/installed")
     @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<InstalledPluginDto> listInstalledPlugins (
             @Context SecurityContext context,
             @FormParam("super_client_id") String superClientId,
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/QueryReferenceController.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/QueryReferenceController.java
index 012bc97..3c93e50 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/QueryReferenceController.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/QueryReferenceController.java
@@ -50,6 +50,7 @@
 @Path("{version}/query")
 @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class,
         BlockingFilter.class, PiwikFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class QueryReferenceController {
 
     @Autowired
@@ -120,7 +121,6 @@
      */
     @GET
     @Path("~{createdBy}/{qName}")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class,
         DemoUserFilter.class, PiwikFilter.class })
     public QueryDto retrieveQueryByName (
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/UserGroupController.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/UserGroupController.java
index efab410..2d053fa 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/UserGroupController.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/UserGroupController.java
@@ -52,6 +52,7 @@
 @Path("{version}/group")
 @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class,
         BlockingFilter.class, PiwikFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class UserGroupController {
 
     @Autowired
@@ -74,7 +75,6 @@
      * 
      */
     @GET
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<UserGroupDto> listUserGroups (
             @Context SecurityContext securityContext) {
         TokenContext context =
@@ -104,7 +104,6 @@
      */
     @GET
     @Path("list/system-admin")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<UserGroupDto> getUserGroupBySystemAdmin (
             @Context SecurityContext securityContext,
             @QueryParam("username") String username,
@@ -132,7 +131,6 @@
      */
     @GET
     @Path("@{groupName}")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public UserGroupDto retrieveUserGroup (
             @Context SecurityContext securityContext,
             @PathParam("groupName") String groupName) {
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/UserSettingController.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/UserSettingController.java
index 3ff57a7..dd8d6cd 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/UserSettingController.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/UserSettingController.java
@@ -44,6 +44,7 @@
 @Path("{version}/{username: ~[a-zA-Z0-9_.]+}/setting")
 @ResourceFilters({ AuthenticationFilter.class, APIVersionFilter.class,
         PiwikFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class UserSettingController {
 
     @Autowired
@@ -102,7 +103,6 @@
     @GET
     @ResourceFilters({ AuthenticationFilter.class, PiwikFilter.class,
             BlockingFilter.class })
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public Response retrieveDefaultSetting (@Context SecurityContext context,
             @PathParam("username") String username) {
         TokenContext tokenContext = (TokenContext) context.getUserPrincipal();
diff --git a/full/src/main/java/de/ids_mannheim/korap/web/controller/VirtualCorpusController.java b/full/src/main/java/de/ids_mannheim/korap/web/controller/VirtualCorpusController.java
index a0019cf..19e4b2b 100644
--- a/full/src/main/java/de/ids_mannheim/korap/web/controller/VirtualCorpusController.java
+++ b/full/src/main/java/de/ids_mannheim/korap/web/controller/VirtualCorpusController.java
@@ -63,6 +63,7 @@
 @Path("{version}/vc")
 @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class,
         BlockingFilter.class, PiwikFilter.class })
+@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
 public class VirtualCorpusController {
 
     @Autowired
@@ -135,7 +136,6 @@
      */
     @GET
     @Path("~{createdBy}/{vcName}")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     @ResourceFilters({ APIVersionFilter.class, AuthenticationFilter.class,
         DemoUserFilter.class, PiwikFilter.class })
     public QueryDto retrieveVCByName (
@@ -156,7 +156,6 @@
 
     @GET
     @Path("/koralQuery/~{createdBy}/{vcName}")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public JsonNode retrieveVCKoralQuery (
             @Context SecurityContext securityContext,
             @PathParam("createdBy") String createdBy,
@@ -175,7 +174,6 @@
     
     @GET
     @Path("/field/~{createdBy}/{vcName}")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public JsonNode retrieveVCField (
             @Context SecurityContext securityContext,
             @PathParam("createdBy") String createdBy,
@@ -209,7 +207,6 @@
      * @return a list of virtual corpora
      */
     @GET
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<QueryDto> listAvailableVC (
             @Context SecurityContext securityContext,
             @QueryParam("username") String username) {
@@ -246,7 +243,6 @@
      */
     @GET
     @Path("~{createdBy}")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<QueryDto> listUserOrSystemVC (
             @PathParam("createdBy") String createdBy,
             @Context SecurityContext securityContext) {
@@ -284,7 +280,6 @@
      */
     @GET
     @Path("list/system-admin")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<QueryDto> listVCByType (
             @Context SecurityContext securityContext,
             @QueryParam("createdBy") String createdBy,
@@ -406,7 +401,6 @@
      */
     @GET
     @Path("access")
-    @Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
     public List<QueryAccessDto> listVCAccesses (
             @Context SecurityContext securityContext,
             @QueryParam("groupName") String groupName) {
diff --git a/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ClientControllerTest.java b/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ClientControllerTest.java
index 880d8f2..554d184 100644
--- a/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ClientControllerTest.java
+++ b/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ClientControllerTest.java
@@ -217,7 +217,8 @@
                         OAuth2ClientType.PUBLIC, "A public test client.");
         clientJson.setRedirectURI(redirectUri);
         Response response = registerClient(username, clientJson);
-        testInvalidRedirectUri(response.readEntity(String.class), false,
+        testInvalidRedirectUri(response.readEntity(String.class), 
+                response.getHeaderString("Content-Type"),false,
                 response.getStatus());
 
         // localhost is not allowed
@@ -231,7 +232,8 @@
         redirectUri = "https://public.client.com/redirect.html#bar";
         clientJson.setRedirectURI(redirectUri);
         response = registerClient(username, clientJson);
-        testInvalidRedirectUri(response.readEntity(String.class), false,
+        testInvalidRedirectUri(response.readEntity(String.class), 
+                response.getHeaderString("Content-Type"),false,
                 response.getStatus());
     }
     
diff --git a/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ControllerTest.java b/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ControllerTest.java
index f31596f..cf42f7e 100644
--- a/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ControllerTest.java
+++ b/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2ControllerTest.java
@@ -174,8 +174,10 @@
     public void testAuthorizeDifferentRedirectUri () throws KustvaktException {
         String redirectUri = "https://different.uri/redirect";
         Response response = requestAuthorizationCode("code",
-                confidentialClientId, redirectUri, "search", state, userAuthHeader);
-        testInvalidRedirectUri(response.readEntity(String.class), true,
+                confidentialClientId, redirectUri, "", state, userAuthHeader);
+        
+        testInvalidRedirectUri(response.readEntity(String.class), 
+                response.getHeaderString("Content-Type"),true,
                 response.getStatus());
     }
 
@@ -201,7 +203,8 @@
         Response response = requestAuthorizationCode("code",
                 publicClientId2, "http://public.com/index.html#redirect", "search",
                 state, userAuthHeader);
-        testInvalidRedirectUri(response.readEntity(String.class), true,
+        testInvalidRedirectUri(response.readEntity(String.class), 
+                response.getHeaderString("Content-Type"),true,
                 response.getStatus());
     }
 
@@ -210,8 +213,9 @@
         // host not allowed by Apache URI Validator
         String redirectUri = "https://public.uri/redirect";
         Response response = requestAuthorizationCode("code",
-                publicClientId2, redirectUri, "search", state, userAuthHeader);
-        testInvalidRedirectUri(response.readEntity(String.class), true,
+                publicClientId2, redirectUri, "", state, userAuthHeader);
+        testInvalidRedirectUri(response.readEntity(String.class), 
+                response.getHeaderString("Content-Type"),true,
                 response.getStatus());
     }
 
diff --git a/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2TestBase.java b/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2TestBase.java
index 48d888c..df15f81 100644
--- a/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2TestBase.java
+++ b/full/src/test/java/de/ids_mannheim/korap/web/controller/OAuth2TestBase.java
@@ -434,8 +434,8 @@
         return JsonUtils.readTree(entity);
     }
     
-    protected void testInvalidRedirectUri (String entity, boolean includeState,
-            int status) throws KustvaktException {
+    protected void testInvalidRedirectUri (String entity, String contentType,
+            boolean includeState, int status) throws KustvaktException {
         JsonNode node = JsonUtils.readTree(entity);
         assertEquals(OAuthError.CodeResponse.INVALID_REQUEST,
                 node.at("/error").asText());
@@ -445,6 +445,7 @@
             assertEquals(state, node.at("/state").asText());
         }
 
+        assertEquals("application/json;charset=utf-8", contentType);
         assertEquals(Status.BAD_REQUEST.getStatusCode(), status);
     }
 }