Help with phone registration with new PBX

Just recently replaced an old PBX at one of the offices that I support. The phones were previously registering via chan sip but for the new PBX I opted to set them up as PJSIP. I also created new secret passwords instead of using the pre supplied secret password within the PBX admin portal. I knew something weird was happening when I went to Reports > Asterisk Info > Peers; and noticed that some of the phones were registering but others were not. Ideally I was thinking that none of the phones should be registering as I changed them to PJSIP as well as changed the secret password. I logged into a phone that was showing as registered and changed the password to what I had set on the PBX system and also changed the port from 5060 to 5160 for PJSIP. Immediately upon doing that - the phone went from registered to registered failed.

I’m drawing a blank here on what the issue could be and how some of these phones are even registering to begin with. Any help would be greatly appreciated.

Appliance: Clearly IP 710
Phones: Yealink T42g

edit: I changed the extension back to SIP on the PBX server and changed the port on the phone gui to 5060 - no change. device still doesn’t register.

Try asking them.