@cynjut - Thank you for clarifying.
Yes, based on my understanding, about two weeks ago @tm1000 stated that v13 now allows no-authentication in this post (final mention towards bottom):
I may be misunderstanding that post, though – because based on your suggestion, switching to SIP from PJ-SIP did solve my problem.
Does anyone have any official word on whether PJ-SIP will allow no-authentication (empty user/secret) and if not, whether it’s something we’ll see in v14?
Thanks again for the insight!