AIO signaling server validate ssl cert

Nextcloud AIO v7.9.0
Hi All,
I used nextcloud with a letsencrypt wildcard certificate and everything worked fine. Later I bought a wildcard on my hosting and after that I got a signal server error.
P.S. With new wildcard works only after the checkbox “Validate SSL certificate” is disabled. With old letsencrypt wildcard everything works without problems.
What could be wrong?

lot of things. e.g. your new certificate issues is not on the trusted CA list… without any details and logs we can only guess. please collect more details