I would like to make calls with FreePBX via Swisscom (Swiss telephone provider). I already have the so-called SIP credentials. Is the following tutorial video wrong? Where can I get better information for my purpose? Many Thanks.
(=FreePBX 15/Asterisk 16 - Register on the Telekom GermanyLAN SIP trunk)
The documentation is that documentation that Swisscom provide that should allow a competent user to configure a system to work with them. You config(uration) is what you have attempted so far.
The video is sufficiently long that few are going to look at it, and, in any case, it is difficult to spot errors if you don’t have some clues in terms of the error messages, and other symptoms, that result in practice.