Our SIP 403 error states that Bearer capability is not authorized??
This probably means the server does not like your username and/or password. Please check them and try again.
But this is across our entire company and it works sometimes and then goes down for hours other times.
Please contact your PBX vendor or administrator for assistance, we will not be able to help with that. If it happens for the complete company, it will not be a client side problem
same here my user names are saved and they all seem to not be registering.
Are you using the same provider by any chance ? It can't be an issue on the Zoiper side. (we don't control zoiper remotely, if it worked before it should keep working)