My desktop dialer keeps ringing after I have answered the call

Question

For some reason, I now get a pop up bubble to answer, along with the program popup itself (which I have only get recently)

Problem seems to have come up since using premium.

The dialer still rings as if I havent answer it, but I have.

I am then mid conversation and Zoiper cuts the call like I haven't answered (in line with my providers cut off time for unanswered calls)

Comments

The only difference between Zoiper Pro and Free is the larger codec list which could lead to some packets being filtered by SIP ALG or some firewalls with UDP transport, because the packets could become very large in some cases. Or the presence options. In general Zoiper5 Free and Pro are exactly the same.

When your firewall or PBX starts filtering the packets, this could lead to negotiation issues which could look very similar to what you have described.

I can also suggest that you first try disabling the "Subscribe Presence" and "Publish Presence" options from Zoiper -> Settings -> Accounts -> select your account -> Advanced. Some server reject those and after some rejection attempts could block the UA for some short amount of time or stop responding overall.