Forward traffic from a router to a port on another router

Hi

i have a mikrotik router with 2 wan’s

using mangle as routing mark to rout some users to the second port works well

however i have a client that also uses mikrotik router but routing mark on his IP stops him form accessing the internet

please advice

Routing marks are not passed from mikrotik to mikrotik, they are internal to that router ONLY.

That being said the issue is probably an IP conflict.