0 votes


I bought and installed Zoiper recently on my Windows 10 PC. It was working great.

As soon as I upgraded it to the Pro version, all incoming calls were automatically routed to my PBX voicemail. I can still make outgoing calls without issues. 

I can see for a very short time an incoming call notification (like 1/10 second) but I never have the chance to "answer" the call.

Zoiper registers the call as follow

Missed call from Phone (anonymous).
4:07 PM
Can't find matching codec in SDP (code: 2)


If I call from another extension internally, I get the same error.

I uninstalled Zoiper and then re-installed as the free version using all default settings. Once again I can receive phone calls.

We have this problem on 2 different computers

What can I do to investigate/fix the issue?


in Windows by (120 points)

Zoiper5 Pro has very large codec list which could lead to packet truncating in some cases by NAT or firewalls.

Can you try going to Zoiper -> Settings -> Accounts -> select your account -> advanced -> locate the "Audio codecs" section and disable all codecs which are unneeded and will be unused. Confirm them with your VoIP service provider(PBX administrator).

Try also disabling the "Subscribe Presence', "Publish Presence" and BLF from your SIP account configuration. 

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