This error seems to be recurring one, as it was already encountered by many FIFA 21 and FIFA 22 players. If you visit the EA Answers, help forums, you will find that there is no official solution available but according to some users, you can do the following to fix this issue.
Close FIFA 23 and restart the game
Change the DNS of your internet network
Uninstall and reinstall your game if you have a sufficient connection, but this solution will be a last resort
If you encounter this problem, you can check with the FIFA Direct Communication Twitter account, which will inform if a bug is in progress.
Finally, if you are still unable to connect to the game and there is no information available on the Twitter account or on the server page, we advise you to submit a service ticket on EA Help.