I have been using Zoiper for some time. I moved my desk to a new room this week.
When Zoiper is open I get a constant stream of Windows notifications (one "ding ding dong" sound every 5 seconds) saying
Audio Device has been removed
High Definition Audio Device
Zoiper5 5.3.4 for windows 32 bit
I have tried enabling all audio devices, disabling all audio devices but that did not help. Ironically what does help is unplugging my speakers but... then I can't use Zoiper. As soon as I plug my speakers in again, the windows notificactions return to inform me that the audio device has been removed.
My audio settings in Zoiper are as follows:
When I call the number, the ringtone plays fine through the speakers.