SIP 403 / Bearer capability not authorized

I need some help because I can’t configure my softphone. I use Zoiper. I receive this message : "
SIP 403 / Bearer capability not authorized

SIP 403 is shown when the server understands your request, but is refusing to fulfill it.

Contact your VoIP provider for assistance."

I use Asterisk on my own server. It runs on linux. I use softphone on Windows 2010 and Linux Ubuntu 20.04

Generally, if you want help with Asterisk, you need to provide the diagnostics produced by Asterisk, rather than the phone. However I suspect that either one side is asking for encryption when it isn’t enabled on the other, or the Contact header is specifying UDP when only TCP is enabled or vice versa.

I have found this message with Zoiper when there is a codec issue

Hi,
I really thank you for your answer. But I don’t still see how I can fix it. I also read that it could be a problem with the username format or the password format at the starting inscription with Zoiper5. I forgot to say that I was a newbie.
Which are le th log do I have to see first ?
Thank you.

OK. Now everything is fine. I checked the sip.conf and the phone number. I used to put a phone number which is different from the file. I thank you for your help.