diff --git a/scm-webapp/src/main/java/sonia/scm/security/ScmRealm.java b/scm-webapp/src/main/java/sonia/scm/security/ScmRealm.java
index cb198ada2b..6d0d246906 100644
--- a/scm-webapp/src/main/java/sonia/scm/security/ScmRealm.java
+++ b/scm-webapp/src/main/java/sonia/scm/security/ScmRealm.java
@@ -217,7 +217,7 @@ public class ScmRealm extends AuthorizingRealm
     AuthenticationToken authToken)
     throws AuthenticationException
   {
-    if ((authToken instanceof ScmAuthenticationToken))
+    if (!(authToken instanceof ScmAuthenticationToken))
     {
       throw new UnsupportedTokenException("ScmAuthenticationToken is required");
     }