roundcube problems

I just installed the panel and almost finished installing my site!

I only got a bug!

When I try to open the webmail, it detects the name of my server as if it were a domain and when I change it to my domain name in the Inteet bar, it does not recognize it!

Eg my webmail address should be mydomain.com/roundcube

and when I click on the webmail section, it opens the address my-server/roundcube considering that (my-server) is not a domain, but the name that I gave to my server

Is there someone who has happened to him? And if so, how did you solve it?

Thanks in advance