diff --git a/src/com/gitblit/RedmineUserService.java b/src/com/gitblit/RedmineUserService.java
index 504593f..84194d5 100644
--- a/src/com/gitblit/RedmineUserService.java
+++ b/src/com/gitblit/RedmineUserService.java
@@ -102,6 +102,11 @@
         	}
         }
         
+        if (StringUtils.isEmpty(jsonString)) {
+        	logger.error("Received empty authentication response from Redmine");
+        	return null;
+        }
+        
         RedmineCurrent current = null;
         try {
         	current = new Gson().fromJson(jsonString, RedmineCurrent.class);