I have changed my main domain back to the x10hosting sub-domain but when trying to change it back to the regular domain it says "The domain you have supplied is already in use."
I have changed my main domain back to the x10hosting sub-domain but when trying to change it back to the regular domain it says "The domain you have supplied is already in use."
etiv.etiv.in is listed as a subdomain. If you are trying to add etiv.in , that is the reason.
Remove the subdomain (which you should have done before removing the main domain) and then try again.
Nothing is always absolutely so.