diff --git a/fhem/contrib/betateilchen/57_Calendar.pm b/fhem/contrib/betateilchen/57_Calendar.pm
index bc7cbc033..1c79c3ce6 100644
--- a/fhem/contrib/betateilchen/57_Calendar.pm
+++ b/fhem/contrib/betateilchen/57_Calendar.pm
@@ -1725,7 +1725,7 @@ sub Calendar_Define($$) {
     $hash->{DEF} = "$a[2] $a[3] $url";
   }  
 
-  $url =~ /(^https?:\/\/.*google.*\/)(private-.*)(\/.*)/;
+  $url =~ /(^https?:\/\/.*google.*ical\/)(.*private-.*)(\/.*)/;
   if($2) {
     # private key found in url, store it in keystore
     setKeyValue($name,$2);