Incoming calls dropping

[AugustinasB]

Hello,

Some of the incoming calls are dropping after a few signals if not answered and a few seconds when answered. If answered, both ends of the call can't hear each other. This happens on Polycom VVX phones. User activity report is showing diagnostic ID: 13015. How to fix this?

We are using Skype For Business server 2015.

[#2]

I do tech support for a local college, and I have a user, an instructor, who uses a MAC. She has a similar problem, see her description below....

My Skype seems way off………meaning, if someone calls me, I get an email saying missed call…….I have to quit Skype and restart Skype…..then I can answer the call……..then if I am going to make a call, it doesn’t work….I have to quit Skype again, restart, then make a call

She is on MAC Book Pro running Office for MAC 16.36 with IOS Catalina V 10.15.3 installed.

She has cleared her cache per the following instructions.. https://www.uc.solutions/Skype_for_Business/Skype_for_Business_Client/MAC_Users/Clearing_Skype_for_B...

Does anyone have any ideas on what is going on and how to fix it?

Thanks to anyone who tries to help,

Ralph