Play Voicemail or Record greeting not working

Hello all,

We have a newly built FreePBX 13 install with all of the REST apps working, with the exception of the VM rest app. When attempting to play a voicemail from the VM rest app, it will simply not play. There is no error on the phone itself. When attempting to record a new greeting (or name) from the rest app, it does the same thing. Auto answer is enabled. We are using pjsip.

The log has the following line whenever we attempt to do either:

WARNING[10879]: chan_sip.c:6046 create_addr: Purely numeric hostname (222), and not a peer–rejecting!

Any suggestions?