Communication between PUN and realtime c++ SDK

I wrote a demo that has 2 clients one in Unity and another in Unreal. They were able to communicate between eachother 6 months back.But now the Unity version (using PUN ) and the Unreal version using c++ sdk can't seem to join the same room. I checked the logs and both the applications join the same master server. I was able to communicate between Unity and Unity / Unreal and Unreal but not between Unity and Unreal. I tested it on a local onpremise server and that works but cloud doesn't seem to work. This is critical for the project I am working on any help in this matter is appreciated.