[Dovecot] Syslog-ng match fixes

data/Dockerfiles/dovecot/syslog-ng-redis_slave.conf

@@ -31,7 +31,10 @@ destination d_redis_f2b_channel {
   );
 };
 filter f_mail { facility(mail); };
-filter f_replica { not match("User has no mail_replica in userdb" value("MESSAGE")); };
+filter f_replica {
+  not match("User has no mail_replica in userdb" value("MESSAGE"));
+  not match("Error: sync: Unknown user in remote" value("MESSAGE"));
+};
 log {
   source(s_src);
   filter(f_replica);

data/Dockerfiles/dovecot/syslog-ng.conf

@@ -31,7 +31,10 @@ destination d_redis_f2b_channel {
   );
 };
 filter f_mail { facility(mail); };
-filter f_replica { not match("User has no mail_replica in userdb" value("MESSAGE")); };
+filter f_replica {
+  not match("User has no mail_replica in userdb" value("MESSAGE"));
+  not match("Error: sync: Unknown user in remote" value("MESSAGE"));
+};
 log {
   source(s_src);
   filter(f_replica);