I clicked on list domain names or something beside the name server and now I can't delete the name server for the domain name anymore. I did a manual edit, but I think I was supposed to leave IP to the default one. Help please,
Hmm, it sounds like you want to delete a name server listed in your account, but you can't because it is still being "used" by a domain in your account.
What you need to do is look at the name server settings for your domains and check if the name server you want to delete is listed as a default name server in the "Name Servers" box under option 2. (The part which has the drop down menus for your name servers.)
Set the name servers to another name server or to the "None" value in the drop down menu and click the "Select Name Servers" button to save your changes. Then reset the name server option to the one you want your domain to use. You will need to do this for all domains in your account.
Yes, we do acknowledge that this is a kind of round-about way of deleting a name server from your account (especially if the domain isn't even using name server), but at the moment, this is the only way to do it. We will be changing this in the future when we have time.
If you are trying to set it so that Dynadot is your name server again, just go to your domain, choose Select Name Severs, and set your domain to use any Dynadot service.