Important: You are supposed to have assigned mypanel.mydomain.mytld as your Sentora sub-domain.
(Replace each occurance of mypanel.mydomain.mytld and mydomain.mytld with your own domain info)
'When I try to browse the URL http://mypanel.mydomain.mytld for the Sentora login page it does not work
Normally it should have been setup by your registrar and should work. If not, try first to reset it in its default state or ask your registrar for help.
Note: you are advised to first check that your server and your panel works with your registrar nameservers before attempting to use your own (or any other) nameservers.
If some errors are reported, resolve them first. Web search engines (Google, Bing, Yahoo, etc) are your friends, but also the pages Setting up DNS ... and domain consideration in First connection to Sentora.
With Ping.eu check that the sub-domain mypanel.mydomain.mytld does resolve to an IP.
If you get ** server can't find mypanel.mydomain.mytld, the sub-domain has no record in the nameservers.
Create it as CNAME record pointing to your main domain ( usually @ ) with the manager of your domain nameservers reported in 1).
Check also thst the sub-domain has been propagated up to your region with Global DNS Propagation Checker.
During Sentora installation, did you enter correctly the panel sub-domain at FQDN question?
You can check the domain used from SSH console by using this command:
setso --show Sentora_domain
If the response is not something like mypanel.mydomain.mytld (subdomain missing), use this doc page Change Sentora sub-domain