I have a problème with my jabber 10.5 windows. When I receive a pop-up for incoming call, I don't have a button to decline calls, you can show in the attached image. I don't have this problème with Jabber Iphone or android, I have it oly in jabber Windows.
For information :
Do you have a valid VM configuration in place?
Does the device that is calling has access to reach the VM pilot and ports??
If the button is not usable, this is because there is lacking a VM config, or an incorrect config VM/CSS config is in place.
VM = voice mail
Not using CSS and partitions is possible, but you'll only run into trouble down the road, doing that is a very poor design.
No, you need a voicemail system, decline is meant to direct the calling party to your voicemail.
The very same way that you installed cucm and im&presence servers. install cuc v9 and have it integrated with cucm using the application integration wizard within cucm.
I hope your problem gets sorted.
I have a costumer in the same type of infra (CUCM & IMP)
There is no possibility to decline an incoming call on jabber.... with the LAST version of jabber.... today.... in 2017......