Hi Andreas:
can you try the attached patch? Just add the line as shown in the patch. It should allow "PRACK" messages and make the stack reply to them correctly.
Thank you for this - the signalling should now work correctly, as the call connects immediately once the internal extension 221 (against which osmo-cc-sip-endpoint registers) is called. There is one issue remaining - once connected, no audio is transmitted. I don't believe this is related to this patch, though, as my Sipgate account continues working normally with the patch applied. As I am testing this in an openSUSE VM, I suspect it will be more of a firewall issue - or perhaps yet another Auerswald issue. I will be looking into this in more detail a little later today. I'm also attaching a SNGREP capture just in case this were helpful. Thank you and
best regards, Markus