diff --git a/lib/Kalamar/Plugin/Auth.pm b/lib/Kalamar/Plugin/Auth.pm
index cf06321..bdb988d 100644
--- a/lib/Kalamar/Plugin/Auth.pm
+++ b/lib/Kalamar/Plugin/Auth.pm
@@ -450,19 +450,14 @@
       state $r_url = Mojo::URL->new($c->korap->api)->path('oauth2/authorize');
 
       my $client_id = $param{'client_id'};
-      
-      my $query = {
-        response_type => 'code',
-        client_id     => $client_id,
-        redirect_uri  => $param{'redirect_uri'},
-        state         => $param{'state'},
-        scope         => $param{'scope'},
-      };
-      
-      my $url = $r_url->clone->query($query);
-      
-      return $c->korap_request($no_redirect_ua, get => $url)
-      ->then(
+
+      return $c->korap_request($no_redirect_ua, post => $r_url, { } => form => {
+          response_type => 'code',
+          client_id => $client_id,
+          redirect_uri => $param{'redirect_uri'},
+          state => $param{'state'},
+          scope => $param{'scope'},
+        })->then(
           sub {
             my $tx = shift;
 
diff --git a/t/server/mock.pl b/t/server/mock.pl
index 134fb97..0aa8a9b 100644
--- a/t/server/mock.pl
+++ b/t/server/mock.pl
@@ -848,7 +848,7 @@
   );
 };
 
-get '/v1.0/oauth2/authorize' => sub {
+post '/v1.0/oauth2/authorize' => sub {
   my $c = shift;
   my $type = $c->param('response_type');
   my $client_id = $c->param('client_id');