I'm using Zoiper v3.3.21933 with SIP account.
Sip account has been configured with Tehacom to Asterisk.
All the configurations on Asterisk backend is working fine. I've tested settings with Windows Zoiper and iPhone Zoiper and everything works fine.
On Mac OSX platform is problematic. For some reason I get SIP 503 error : Certificate Validation Failure. It makes no difference whatever I choose in Zoiper's Certificate settings (Don't use, Use default and so on...)
Do anyone have ideas how to make Mac OS X version working?
If you need more info, feel free to ask!