diff --git a/FHEM/74_THINKINGCLEANER.pm b/FHEM/74_THINKINGCLEANER.pm
index 979ddc2b0..66bfd9186 100644
--- a/FHEM/74_THINKINGCLEANER.pm
+++ b/FHEM/74_THINKINGCLEANER.pm
@@ -883,6 +883,12 @@ sub THINKINGCLEANER_Attr(@) {
         && $attrName eq "webhookHttpHostname"
         && $attrVal !~ /^([A-Za-z_.0-9]+\.[A-Za-z_.0-9]+)|[0-9:]+$/ );
 
+    return
+"Invalid value for attribute $attrName: needs to be different from the defined name/address of your Roomba, we need to know how Rooma can connect back to FHEM here!"
+      if ( $attrVal
+        && $attrName eq "webhookHttpHostname"
+        && $attrVal eq $hash->{DeviceName} );
+
     return
 "Invalid value for attribute $attrName: FHEMWEB instance $attrVal not existing"
       if (