diff --git a/R/matomoquery.R b/R/matomoquery.R
index e530d4b..28ad2f0 100644
--- a/R/matomoquery.R
+++ b/R/matomoquery.R
@@ -22,6 +22,7 @@
 #' @importFrom dplyr mutate rowwise bind_rows select summarise n
 #' @import tibble
 #' @importFrom magrittr %>%
+#' @importFrom stringr str_replace str_replace_all
 #' @importFrom utils head tail
 #'
 #' @examples
@@ -50,7 +51,6 @@
       call. = FALSE
     )
   }
-
   httr::GET(
     url = matomoUrl,
     query = list(
@@ -58,7 +58,7 @@
       method = getMethod,
       format = "json",
       idSite = paste0(siteId, collapse = ","),
-      date = date,
+      date = str_replace_all(date, " *UTC", ""),
       period = period,
       filter_limit = filter_limit,
       language = "de",
@@ -75,16 +75,18 @@
   }
 
   json <- httr::content(res, "text", encoding = "UTF-8")
-
+  warning(json)
   l <- jsonlite::fromJSON(json)
+
   if("result" %in% colnames(l) && l$result == 'error') {
     stop(paste("in api call:", l$message), call. = FALSE)
   }
 
   if (period=="range") {
-    df <- if (length(siteId) == 1) {
-      l %>%
-        mutate(site_id=siteId)
+    df <- if (is.list(l) && length(l) == 0) {
+      warning("API call returned an empty list.\n", call. = FALSE)
+    } else if (length(siteId) == 1) {
+      l %>%  mutate(site_id=siteId)
     } else {
       bind_rows(jsonlite::fromJSON(json), .id = "site_id")
     }