Thanks, it helped!in case there is NAT between server and client: google "AssumeUDPEncapsulationContextOnSendRule"
Due to a this bug in 6.42.x:May I ask why downgrade to such a vulnerable version? Wouldn't be better to upgrade the other equipment if having the same version on all hardware is important?
But why??This is correct behavior.
Have you tried TP-Link or D-Link?
I am sure they are much easier with all their wizards whistles and bells.
If you find RouterOS hard, then it's probably not for you.