@suprise-attack When you click reply, a window will open up. Beneath where it says “Replying to …” there are a series of icons. The one farthest to the right is to upload an attachment. You can add your game file as an attachment to your post. I think it works anyway. I haven’t got a reply from my opponent yet lol.
incorrect Triplea version…check to make sure you have the latest (1.25 i think).
that you haven’t dled the proper maps…make sure you’ve done this.
if it’s that you can’t host that’s the problem, you probably haven’t enabled port forwarding to host games.
They explain how to do all this in the link above.