[Linphone-users] Error 503 (Service Unavailable) with outgoing call

[Frank Michler]

Hi,

I have a problem with outgoing calls with linphone. linphone can successfully 
register with the sip server, and can also receive incomming calls. But when 
initiating outgoing calls I receive the following error from the sip server:

503 Service Unavailable
Q.850 ;cause=42 ;text="3"

Some more information:
-  the SIP provider is arcor (xxxxx.sip.arcor.de now owned by Vodafone)
- I am using Linphone 3.8.5
- I was able to do outgoing calls using another VoIP client (sflphone)
- I get the same error on my smartphone using Linphone for android (Linphone 
2.4.1)
- on Android I can successfully do outgoing calls with a different client 
(CSipSimple)

linphone is doing something differently compared to other clients. 

Do you have any idea what this could be? Can this be a configuration issue? Or 
a difference in the implementation of the sip protocol?

I have already tried to compare the sip traffic with what happens with sflphone 
(using wireshark), but didn't find a significant difference in the INVITE 
request. But maybe I don't know what to look for ...

Hope someone can help,

Best regards, Frank.