Can only join but can't create a match! Please Help!

[ltbpc]

HI
I wonder if you can help me. Ive just started playing on here again after years away and have signed up for some tournaments.
I have tried everything but I cannot create a match online, I can only join it! It gives me an error about ports 4321. I have tried to open this in my router and have turned off all antivirus software etc. Still I cannot create a game. This used to work no problem but now just keeps giving me the error.

Also do I have to use Discord? or can I just use the messages service on here ?
thanks
Rob