"Connecting to Ultimate Team is not possible at the moment."
I have tried absolutly every solution I can think of. And as a Tech Engineer, I have executed an extremely big troubleshooting process. I see many poeple having this issue, and it is 100% on EA's side!
I've seen other similar reports of this issue after disconnecting or abandoning a gauntlet match, and we've informed our teams.
In the meantime, though, deleting the squad data on the apps and leaving an empty squad set as active worked for other players, as it completely refreshed the corrupt squad data that seems to be causing the problem.
If you get an error when you try to access the Companion app or the Web app, please wait a bit longer after closing the game before logging in to the app, 30 minutes should be enough for the game session to close completely.