Two player career mode won't open

My mate and I have been trying for days to get a co-op career up and running like we did last year, but only one of us can join the lobby at a time. When one player joins, the second player attempts to load in before being hit with 'Unable/Failed to connect to EA server'.

We've tried everything.. reinstalling the game, deleting all game files from console and cloud, switching from LAN connection to WiFi (we both have lightning fast internet speeds and cat6 LAN cables), and even resetting/modifying our DNS settings.

We can both join other online modes with no issue. At a complete loss here. Co-op Career is literally the single reason we purchased the game.

(We're both in Australia for what it's worth).