Thanks, I wasn’t sure after there was no answer at all.
In my case the initial problem was the statement “method=tlsv1”, which should have been “method=ssl23.” Somebody else with a deeper knowledge of openssl help me by pointing out that tlsv1 unnecessarily restricts what openssl can negotiate. If the other side doesn’t want tlsv1, you are out of luck.
Now that REGISTER, OPTIONS, etc works, I don’t get any media stream to work, but that’s something for tomorrow.
Yes, the default of PJSIP is TLS 1.0-only and therefore a disaster. With that parameter value above, you change to auto-negotiation. However, if you upgrade your OpenSSL to 1.1 or newer, PJSIP auto-negotiates even on default. If you want to take greater control about this, there is a dedicated thread…