diff --git a/fhem/FHEM/00_MQTT2_CLIENT.pm b/fhem/FHEM/00_MQTT2_CLIENT.pm
index bc6bf39c5..0a21c1d5b 100644
--- a/fhem/FHEM/00_MQTT2_CLIENT.pm
+++ b/fhem/FHEM/00_MQTT2_CLIENT.pm
@@ -80,6 +80,7 @@ sub
 MQTT2_CLIENT_connect($)
 {
   my ($hash) = @_;
+  return if($hash->{authError});
   my $disco = (ReadingsVal($hash->{NAME}, "state", "") eq "disconnected");
   $hash->{connecting} = 1 if($disco && !$hash->{connecting});
   $hash->{nextOpenDelay} = 5;
@@ -207,6 +208,7 @@ MQTT2_CLIENT_Attr(@)
 
   my %h = (clientId=>1,lwt=>1,lwtRetain=>1,subscriptions=>1,SSL=>1,username=>1);
   if($init_done && $h{$attrName}) {
+    delete($hash->{authError});
     MQTT2_CLIENT_Disco($hash);
   }
   return undef;
@@ -237,6 +239,7 @@ MQTT2_CLIENT_Set($@)
 
   } elsif($a[0] eq "password") {
     return "Usage: set $name password <password>" if(@a < 1);
+    delete($hash->{authError});
     setKeyValue($name, $a[1]); # will delete, if argument is empty
     MQTT2_CLIENT_Disco($hash) if($init_done);
 
@@ -314,6 +317,7 @@ MQTT2_CLIENT_Read($@)
                   "bad user name or password", "not authorized");
       Log3 $name, 1, "$name: Connection refused, ".
         ($rc <= int(@txt) ? $txt[$rc] : "unknown error $rc");
+      $hash->{authError} = $rc;
       MQTT2_CLIENT_Disco($hash);
       return;
     }
diff --git a/fhem/FHEM/10_MQTT2_DEVICE.pm b/fhem/FHEM/10_MQTT2_DEVICE.pm
index 828ada690..bf6781adc 100644
--- a/fhem/FHEM/10_MQTT2_DEVICE.pm
+++ b/fhem/FHEM/10_MQTT2_DEVICE.pm
@@ -162,7 +162,7 @@ MQTT2_DEVICE_Parse($$)
         my $ret = json2nameValue($value);
         if(keys %{$ret}) {
           $topic =~ m,.*/([^/]+),;
-          my $prefix = ($1 && $1 !~m/^0x[0-9a-f]+$/) ? "${1}_" : ""; # 91394
+          my $prefix = ($1 && $1 !~m/^0x[0-9a-f]+$/i) ? "${1}_" : ""; # 91394
           $add = "{ json2nameValue(\$EVENT, '$prefix') }";
         }
       }
@@ -184,7 +184,7 @@ MQTT2_DEVICE_Parse($$)
     my $cidArr = $modules{MQTT2_DEVICE}{defptr}{cid}{$newCid};
     if(!$cidArr || !int(@{$cidArr})) {
       my $devName = $newCid;
-      $devName =~ s/[^a-z0-9._]/_/g;
+      $devName =~ makeDeviceName($devName);
       return "UNDEFINED MQTT2_$devName MQTT2_DEVICE $newCid";
     }
     return "";