I may have to eat my words on this one. Forza support was actually helpful here.
After much frustrated digging trying to find the issue, I started checking on the Teredo client as forza support's general response suggested and it actually looks like that may be the problem.
It's all technical but Teredo seems to relate to ipv6 networking.
My firewall logs highlighted an issue.
Try checking windows settings -> Gaming -> Xbox Networking to see what it says. It might report a problem and the Fix it button may help.
Didn't for me, but worth a try.
After a lot of googling I came across an article that suggested that the Teredo server name may be incorrect. I changed mine and fingers crossed, since then I seem to have a more stable Horizon Life connection and I even managed to get in a round of team games.
To see your Teredo settings, from the windows command shell type netsh interface Teredo show state
If your issue is the same as mine then the server name may be wrong.
Naturally, mess with these settings at your own risk or ask someone who knows more about this than I do.
YMMV.
I suspect this is a Microsoft issue from a windows update.
Edited by user Thursday, July 23, 2020 6:13:41 PM(UTC)
| Reason: Not specified