diff --git a/scm-webapp/src/main/java/sonia/scm/api/rest/resources/AbstractManagerResource.java b/scm-webapp/src/main/java/sonia/scm/api/rest/resources/AbstractManagerResource.java
index 10d65a16be..b8a3dfc45d 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/rest/resources/AbstractManagerResource.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/rest/resources/AbstractManagerResource.java
@@ -577,6 +577,9 @@ public abstract class AbstractManagerResource<T extends ModelObject,
     return items;
   }
 
+  // We have to handle IntrospectionException here, because it's a checked exception
+  // It shouldn't occur really - so creating a new unchecked exception would be over-engineered here
+  @SuppressWarnings("squid:S00112")
   private void checkSortByField(String sortBy) {
     try {
       BeanInfo info = Introspector.getBeanInfo(type);
@@ -589,17 +592,17 @@ public abstract class AbstractManagerResource<T extends ModelObject,
     }
   }
 
-  protected PageResult<T> fetchPage(String sortby, boolean desc, int pageNumber,
+  protected PageResult<T> fetchPage(String sortBy, boolean desc, int pageNumber,
     int pageSize) {
     AssertUtil.assertPositive(pageNumber);
     AssertUtil.assertPositive(pageSize);
 
-    if (Util.isEmpty(sortby)) {
+    if (Util.isEmpty(sortBy)) {
       // replace with something useful
-      sortby = "id";
+      sortBy = "id";
     }
 
-    return manager.getPage(createComparator(sortby, desc), pageNumber, pageSize);
+    return manager.getPage(createComparator(sortBy, desc), pageNumber, pageSize);
   }
 
   //~--- get methods ----------------------------------------------------------
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/GroupCollectionResource.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/GroupCollectionResource.java
index 4a9db5662c..912d890fe8 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/GroupCollectionResource.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/GroupCollectionResource.java
@@ -41,11 +41,12 @@ public class GroupCollectionResource {
 
   /**
    * Returns all groups for a given page number with a given page size (default page size is {@value DEFAULT_PAGE_SIZE}).
-   * 
+   *
    * <strong>Note:</strong> This method requires "group" privilege.
-   *  @param page     the number of the requested page
+   *
+   * @param page     the number of the requested page
    * @param pageSize the page size (default page size is {@value DEFAULT_PAGE_SIZE})
-   * @param sortBy   sort parameter
+   * @param sortBy   sort parameter (if empty - undefined sorting)
    * @param desc     sort direction desc or aesc
    */
   @GET
@@ -54,6 +55,7 @@ public class GroupCollectionResource {
   @TypeHint(GroupDto[].class)
   @StatusCodes({
     @ResponseCode(code = 200, condition = "success"),
+    @ResponseCode(code = 400, condition = "\"sortBy\" field unknown"),
     @ResponseCode(code = 401, condition = "not authenticated / invalid credentials"),
     @ResponseCode(code = 403, condition = "not authorized, the current user does not have the \"group\" privilege"),
     @ResponseCode(code = 500, condition = "internal server error")
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserCollectionResource.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserCollectionResource.java
index 008fc08143..c269cd9f90 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserCollectionResource.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserCollectionResource.java
@@ -43,9 +43,10 @@ public class UserCollectionResource {
    * Returns all users for a given page number with a given page size (default page size is {@value DEFAULT_PAGE_SIZE}).
    *
    * <strong>Note:</strong> This method requires "user" privilege.
-   *  @param page     the number of the requested page
+   *
+   * @param page     the number of the requested page
    * @param pageSize the page size (default page size is {@value DEFAULT_PAGE_SIZE})
-   * @param sortBy   sort parameter
+   * @param sortBy   sort parameter (if empty - undefined sorting)
    * @param desc     sort direction desc or asc
    */
   @GET
@@ -54,6 +55,7 @@ public class UserCollectionResource {
   @TypeHint(UserDto[].class)
   @StatusCodes({
     @ResponseCode(code = 200, condition = "success"),
+    @ResponseCode(code = 400, condition = "\"sortBy\" field unknown"),
     @ResponseCode(code = 401, condition = "not authenticated / invalid credentials"),
     @ResponseCode(code = 403, condition = "not authorized, the current user does not have the \"user\" privilege"),
     @ResponseCode(code = 500, condition = "internal server error")