Why are some of my domains not eligible?
While setting up your email account, you might see some domains listed as not eligible or grayed out in your Email & Office Dasboard. This is because you can only have a one type of email account for each domain.
For example, you'll get an error message if you try to set up Microsoft 365 with a domain that's already used by Professional Email.
Microsoft 365 can't be transferred to any other platforms.