FreePBX Firewall - no matching endpoint found

quite easy to disable pjsip, immediately from bash:-

rasterisk -x "module unload chan_pjsip"

then add

noload = chan_pjsip.so

to /etc/asterisk/modules.conf

for permanence over a restart , when chan_pjsip is all working , just delete that line.

just make sure that chan_sip is bound to your preferred port (5060 is probably your worse choice for any number of reasons)

There is no "correct port" neither for sip or pj-sip, the default ones of 5060/5061 will ALWAYS expose you to Chinese professors and knuckledraggers all over the world. been there done that . . .