Forza Horizon 4 won't connect to online session, but does connect to The Trial and...

Are you having any connection issues with other games as well, or is it specifically on Forza Horizon 4 only?

If you try a Horizon Solo session, and then try to switch online, does it give you the same error message?

I have same problem too but worse, I can't even connect Horizon Life servers and The trail too

The annoyingly funny thing about this issue is, my friend’s teredo status says “blocked” while he plays online with other players but here me having this issue to connect online servers while my teredo and everything is fine.

The Horizon Life issue has been going on for getting on for a month now, though it severely worsened last Thursday with the WInter Season which is why I think they finally took notice of it as opposed to ignoring it.

The most recent update to the Series X/S consoles (the one that fixed the game quitting to dashboard) also fixed Horizon Life connection issues mostly

I don't know if these server problems are related to the updates they do for the game.

I remember not long after I installed the game on my Xbox series x last year it received an update a day or 2 later and I started getting a server error message on my Xbox series x yet on my Xbox one x the game played fine without an error message.