Symptoms
When someone calls you on Skype for Business, you do not hear the CX300 phone ring.
Cause
Various
Resolution
1) Check your status in Skype for Business. If it is set to "Busy", "Do Not Disturb", or "In a Meeting", the phone will not ring unless the person calling you has permissions to override your status.
2) Verify that the audio on your computer is not muted.
3) Open Options in Skype for Business, and go to Audio Device. Verify that the default audio device is your Polycom CX300.
4) If you are a member of a response group and want to receive calls to that group, make sure you are signed in to the correct response group.
5) If your device still doesn't ring when you receive calls, unplug your Polycom CX300's USB cable and plug it back in.
OUTCOME
Your Polycom CX300 will ring when you receive calls.