Finally, it works!
I keep the previous configuration that I show you but I delete the WHITH_AUTH define. This way, all sip-phones and softphones register without any problem (no UNAUTHORIZED messages from Kamailio). I can see them in my database, in the “location” table.
Unfortunately, I still don’t understand why I can’t use the authentication option… If you have any suggestions, please let me know.
Thank you for your help,
Regards Gab