[Linphone-users] issues using LinPhone

[Boris]

Hej LinPhone List,

I am new on the list, have installed LinPhone for some time and use it 
regularly.
My thanks go to all who contribute to the software!

I chose LinPhone because it is more or less the standard for IP 
telephony in my favorite Linux distribution (Debian Buster).

Unfortunately I have little knowledge about VoIP. Some problems I can't 
get under control and hope for help here.

I use LinPhone 3.12.0 from the stable repositories of Debian. To test if 
my problems are solved I have already tried the AppImage with version 
4.x. But this did not show any new results. I am not sure what the best 
practice is. I would like to have a LinPhone repository in the 
sources.list. So far I could not get used to AppImages.....

I have configured two SIP accounts in LinPhone. One of them (from TNG) 
runs without problems. Only sporadically I have the effect that a red 
text appears on an outgoing call: Not Acceptable Here 399 
87.137.138.18:5083 "non-audio media not accepted".
This only occurs when dialing certain numbers, other numbers can be called.

My pain is much greater when using LinPhone on a SIP account from 
Deutsche Telefon - attention: not Tele_k_om, but this one: 
https://www.deutsche-telefon.de/
1. outgoing calls can be set up, but are aborted reproducibly after a 
little more than 15 minutes
2. incoming calls cannot be accepted.
For both cases I have provided output from the debug window (anonymized):
https://cation.de/pub/call_logs.zip

I confronted the support at Deutsche Telefon with the matter. There they 
are only moderately cooperative. The logs would not show any reason, but 
probably the refresh period was set to 1800 and would be renewed half 
the time. I should set it to 3600 and check if the time until abort 
changes - it doesn't.
They also advised me to change the refresh from uas to uac. But I don't 
find this paramenter at all.

I would be very happy if LinPhone would run stable - even with the named 
service.

Thanks in advance,

Boris