You are being prevented from completing this action because the email address you are trying to sign-up with is used by an existing Microsoft account. If this is your account, you will need to remove the email address from your Microsoft account before you can continue. Please go to https://account.live.com/names/Manage, sign in and create a new @outlook.com email address; set the new @outlook.com email address as primary and delete the custom email address; go to https://premium.outlook.com and complete the sign up with your custom email address.
You are being prevented from completing this action because one of the aliases you are trying remove is set as your account's ...
You are being prevented from completing this action because the alias you are trying remove is set as your 'Default' email ...
You are being prevented from completing this action because the email address you are trying to add is used by an existing ...
You are being prevented from completing this action because the email address you are trying to add is used in the security ...
You are being prevented from completing this action because the email address you are trying to sign-up with is used by an ...
You are being prevented from completing this action because this alias has to be removed manually from your Microsoft account. ...
You are being prevented from completing this action because you have already changed your domain. You are not allowed to ...
You are being prevented from completing this action because you have used the maximum number of allowed aliases on your Microsoft ...
You are being prevented from removing your domain because your custom email address is set as your account's Primary alias. ...