Hello Experts,
I am having a machine placed at remote location, and on regular basis I required to connect it using remote desktop (mstsc), but some times the remote machine gets hanged as I connects it & requires rebooting.
Note:- mstsc port is opened/allowed for my ip,

I'm not able to understand the reason for this,
Please guide the solution.

I'd say use something like TightVNC or Dameware client instead of the remote desktop connection.

If using another remote product produces the same results, it's possible that your signal is have issues reaching the destination machine. On both machines flush the dns cache. However, it could also be something else, like a particular service running during the time you're trying to connect or whatnot that's using system resources that causes you to hang when you try to connect.