Maintaining Client-Server Version Numbers

Hey everyone, this sounds like the problem I am having but I don’t know for sure.
How do I tell if it’s the version number or something else which gives me the Session Not Found error when trying to connect my slightly-different version of the game for Android with the original version for PC (this worked in the past by the way, when they had the same project file. I had to separate them out because Android doesn’t support one of the non-essential plugins I used for some fun menu effects).

Here’s my post if any of you would be willing to look at it and give me a clue: