@EA_QueenBee It looks like they're on PC. So,
@happyy_not_sadd cross-play isn't optional on PC. Its only optional on consoles.
If you are on console, perhaps you're trying to join a mode that requires it to be enabled, (which I don't think one is active right now, like Rumble), or you're connected to a datacenter server that has little to no players playing, (which could be related to the time of day).