Make sure you have basic authentication enabled because there was a vulnerability recently where accounts got compromised.
Besides that, i love CloudPanel but if you're reselling hosting, it's not very useful.
You probably locked yourself out of the panel by using wrong login credentials? Happened to me once when I was trying to login to the iOS app with the wrong username on the same wifi network and then i couldnt login to plesk anymore.
Next time just check if your personal IP is on the...