Downgrade to Asterisk 13 causes 403 forbidden

I have been trying to switch my asterisk version from 14 to 13 by using the asterisk-version-switch command. Everything looks like it worked fine, the system shows the correct version and I even reboot for good measure. But if I try to do anything from a phone (incoming call, outgoing call, internal call, voicemail, etc) I get a “sip 2.0 403 forbidden” error.

This is on a fresh install of FreePBX 14. Reason I am trying to downgrade is to fix BLF on my Yealink T46’s.