Error "Could not join server (1)

I’ve been having a problem with Battlefield 3 since yesterday. Every time I try to join a server, I get the message:
Could not join the server 1
I’ve been playing this game for years and have over 4200 hours played, mostly on different servers. I haven’t changed any settings recently.
To troubleshoot, I’ve already:
Formatted my PC and did a clean install — the issue persists.
Installed the EA App and the game on a different PC in my home (this one using Wi-Fi), and I’m still getting the same message
Tried joining multiple different servers, but the same error appears on all of them.

Please help me resolve this issue. Thank you in advance.

Best regards