Replying to
@Paul_Taylor@mathstodon.xyz At a "University" I refused to use their M$ "e-mail system" as it failed to be a bonā fidē e-mail system. My supervisor agreed with me that it was not an e-mail system as it did not operate using standard protocols. IIUC, M$ had an exclusivity clause that prevented any other e-mail system from operating within their TLD that did not already predate the contract with M$. Thus there was nothing to be done: use it or else!