Hi. I am facing the same problems. I can not add domains in my aapanel...some times. I was able to add a couple of domains (btw, they do not show in the domain list); fictitious domain names like xyz.com can be added, but no other of my domains except for one, has been added. Also, when I download a domain list, the list is empty.
I tried everything explained here, but nothing worked.
By the other hand, I registered correctly my Name Servers (ns1..., ns2...) in my domain registrar, with the right IP, but they are not showing anywhere in my aapanel.
Your panel is one of the lightest ones I have tried before, and also seems to have everything to run a dedicated server for my domains. I really like it and I would not doubt for an instant to let you my login details if you can please see and check and help me fix what is wrong with it.