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Cisco Jabber on windows drops first call

Good afternoon,


I'm running Cisco Jabber for windows version 12.7.1 on my PC for use as a softphone. Now that I'm working from home more and using it instead of my desk phone, I'm noticing a drop in the first call when I hit the answer button. 

This happens when someone calls me or if I dial out as well. When dialing out, internal or external and hit the green call button or press enter, it goes to the call screen then just drops. My second call right after will go through no problem. 


My thought is that it has something to do with the connection back to my call manager, my softphone is showing registered in CUCM and call alerts come through.


Any ideas on why the connection fails out the first time? Could it be related to a timeout issue with a setting? 


CUCM version 10.5.2


You are saying that you are working from home now.
Are you using expressway or VPN?
Does the jabber work normally when you are in office?

We are using VPN (Checkpoint) which I know isn't Cisco supported. We also have expressway servers for our mobile apps. Office use was mostly for testing, however I would say it worked correctly there. 


VPN is staying connected and we did have to work to open up certain ports. It's strange I see the call come in but it doesn't connect until after the first time. I'm starting to notice around 2 minutes of no calls is when the issue will reappear. 


Thanks for the reply!


I have a user experiencing this same issue. however he is connected via Cisco AnyConnect VPN. Did you ever find a solution?

Adam Pawlowski
VIP Engager

You would need to look at some logging to see what is happening. Jabber isn't necessarily the most expressive when something occurs in the background that's unexpected. It's possible it is attempting an INVITE but it is not presently registered because something has gone amiss in the connection between Jabber and the UCM. You'd see this also perhaps in the logging from the UCM, either device registration or the CM logging of SIP traffic. If the INVITE comes from an unexpected address, endpoint is unregistered, the signalling is being mangled by some ALG, etc, there should hopefully be enough pieces to try and narrow down the culprit.




We found that this issue is only affecting our Windows 8.1 machines with the Realtek audio driver installed. Updating to the latest Realtek drivers did not resolve the issue.

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