Hi,
I'm usually getting Forbidden Code 403 error. Depending on how I change the settings when trying to find out which ones are correct, and while facing no response from Sonetel's techncial support team, I sometimes get this error, sometimes not. Call is usually established for around two seconds and then it automatically ends. Sometimes the call doesn't even start. I also don't hear anything in the working headphones. I followed exact instructions that don't even seem to be accurate and with certainly missing info (e.g. Domain field) on the official webpage:
https://sonetel.com/en/help/help-topics/telephony/make-and-receive-calls-with-sip-phones/most-popular-sip-phones/how-to-connect-zoiper-to-sonetel/
But it doesn't work. Any help how to do outgoing calls would be highly appreciated please. I did not get help from their support.