Do I need to register my app to retrieve mail from an office365 server?
 

A set of instructions for fetching mail with getmail from an office365 server says I must register the app at portal.azure.com. I log in, try to do that, get told that my domain restricts users from registering apps. Is that the end of my quest?

Later: I forgot to mention that I send my mail through this server with sendmail. I never registered the app. I changed nothing in sendmail.cf to make it work.