I bought my domain from a registrar and I want to create a custom business email using google but when I try to sign up with my existing domain name, it shows that the "Domain is already in use". I have read the conditions and none of them apply to me. I then decided to click on the "Fill out this form". When filling out the form, it takes my domain name and a contact email address. I fill that out and submit, and then it gives me "500 That's an error message". I have tried a lot of times but nothing is working out.