It works now. Thanks for your support.
I bought hosting with SSL generated by OVH for the domain www.alesprzedawca.pl in the multisite settings. This topic was not conceded with caddy.
Steps to fix:
- I disabled SSL in
multisitesettings. - I bought a new server and redirected A record of
alesprzedawca.plto a new IP - I set up service on this server, then disabled and removed this server
- Finally, I redirected record A to the old server IP
- Reloaded caddy and I started working
For local debugging, It was useful to use:
sudo systemd-resolve --flush-caches
getent hosts alesprzedawca.pl
dig alesprzedawca.pl
and connect by VPN to skip DNS caches.