Troubles with rpt

HI, i got a problem accessing remote desktop.
recently i’ve changed the ipcop router for a mikrotik rb750.
i’ve configured and everything works fine, except for one thing.
a’m having troubles to access remote desktop, not in my lan, i have 4 server + voip, and dst-nat from this side works well.
accessing from lan to internet, it doesn’t work.
i need rpt to access to servers of my clients, i can only access to a few, i don’t know what can it be.
i ping to name of ip from remote desktop on port 3389, and it doesn’t answer, but in my house works.
i think my rb750 is blocking something, but i don’t knnow what.
any ideas?
i’m having this issues since i’ve changed my router.
thanks.