Mail shows 'Configured by a Profile' with no profiles installed on MacBook Pro

I bought myself a new MacBook Pro-- it's mine and not connected to my work or school in any way. When I attempt to open Mail, it gives the message, "Choose a Mail account provider...", followed by the message, "These settings have been configured by a profile." I checked Device Management in settings and there are no profiles defined.

Just to be clear, my Apple ID is NOT my work email address-- it is a separate personal address on a different provider. And that is the mail account I want to connect to on this MacBook.

What's going on here? Is it possible that my Apple ID has somehow become attached to my work email address and as a result, it believes this Mac should be restricted by my work profile?

Any help on how to resolve this would be greatly appreciated!!

[Re-Titled by Moderator]

Original Title: unable to configure email