diff --git a/src/index.html b/src/index.html
index 9fd9c3e..570f92e 100644
--- a/src/index.html
+++ b/src/index.html
@@ -92,6 +92,11 @@ <h2>
                   .routerName.error.required
                 </div>
               </div>
+              <div class="help-block" ng-show="hasError('routerName')">
+                <div ng-show="wizardForm.routerName.$error.pattern" translate>
+                  .routerName.error.pattern
+                </div>
+              </div>
             </div>
           </div>
 
diff --git a/src/nls/locale-en.json b/src/nls/locale-en.json
index 938708b..24f523a 100644
--- a/src/nls/locale-en.json
+++ b/src/nls/locale-en.json
@@ -5,7 +5,10 @@
     "headline": "Basic router setup",
     "routerName": {
       "label": "Router name",
-      "error.required": "In order to register IPs or generate VPN connection files the router name is required.",
+      "error": {
+        "required": "This field is required.",
+        "pattern":"Special Characters are not allowed."
+      },
       "help": "The router name is needed for ip registration and VPN cert and key generation. Also this name is visible in the <a href=\"http://map.berlin.freifunk.net\">Freifunk map</a> if you decide to share your location.",
       "placeholder": "example: funkenpumpe3000"
     },