Here is the fix for anyone having the error issue when trying to play any game mode in CFB25 Ultimate Team online.
All credit goes to Iceman who post this under one of the error posts.
To fix the UT error, MAKE sure your team lineup is at/under 53 players. Usually 25 offensive, 25 defensive, 2 ST. This leaves you with 1-2 slots in your specialist tab to have players not currently in your lineup. I was at 54 players and had the error for 3 days. I removed 2 non-lineup players from my SubLB and Rushing LE and I am able to play every mode with no issues.
This was Iceman’s original post…For some reason it doesn’t post his EA forums tag when I try to. Just want him to get the credit for it but this works 100% of the time.
*Iceman’s Original Post Below*
I have a theory because I tried the clearing of my roster and the putting just starters in my lineup and was able to play after weeks of not being able to do so I then added my backups to make sure I maximized my Georgia Tech chems (mostly backups lol).
So I checked how many players I had in my lineup and it was well over 53 men. I tried clearing out backups especially in the specialists section to get myself to 53 and I was able to play a solo challenge for the first time in weeks.
I think they have the same roster size limitations present in MUT but unlike MUT they do not alert you to exceeding this limit so you are able to back out of the lineup and try to enter a matchup with an illegal roster but the game hits you with a server issue message.
I recommend people try getting their roster under 53 men and trying it. And remember to double check under specialists positions (it can be easy to forget that your Sub LB and Slot CBs may not be in your regular roster especially if you are maximizing chems via backups).