Can't invite friend to crew

[Hayden]

Like the title says. I've tried everything, restarted the game, private group, open play, I've travelled so I'm right next to him, nothing works. I spent 60 mil on turreted weapons & engineered them so they'd be half-decent so me and my friend can try it out but still constantly tells me "invitee is in a crew" "invitee is incapable of multi-crew"
I'm in a Python, for reference.

[Funkynutz]

Portforwarding...