All Calls Direct to VM on Registered Phones

Internal extension to extension, and all incoming calls are being routed direct to voicemail without the extension ringing.

DND is disabled on all phones. Phones are registered and showing OK in Chan_Sip Peers.

FreePBX Distro 10.13.66-7
Asterisk 13.7.0
Core 13.0.43

Dial status seems to go directly to Busy, instead of ringing. Any troubleshooting tips?

Call trace:

Issue appears to match: Follow me issue