diff --git a/fhem/FHEM/98_DOIFtools.pm b/fhem/FHEM/98_DOIFtools.pm
index b937727f2..a7159b2ab 100644
--- a/fhem/FHEM/98_DOIFtools.pm
+++ b/fhem/FHEM/98_DOIFtools.pm
@@ -373,7 +373,7 @@ sub DOIFtools_eM($$$$) {
         }
       }
   }
-  return $ret;
+  return $ret ? $ret : undef;
 }
 ######################
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