This domain name can’t be used because it contains a protected word or inappropriate language. Please contact support if you feel this is not the case.

Hello,

When I've tried to add domain akfinance.eu to Microsoft custom domain I get this error:

This domain name can't be used because it contains a protected word or inappropriate language. Please contact support if you feel this is not the case.

AK Finanse is a name of financial advisory company. "AK" is the abbreviation of "Anna Król" (name of the owner). "Finanse" is finance (in polish). I work for this company. I've created a website, registered a domain name, and now I would like to create e-mail accounts in outlook.com.