Microsoft 365, how to setup a single user with multiple emails on different domains?

Question

On MS 365, for a single user I'd like to setup two real emails: [email protected] and [email protected].

[email protected] is well setup. Now I'm trying to add [email protected].

So far I tried to add [email protected]

• as an aliases but it's not a real email
• as a distribution list that can receive email from outside the organisation and where [email protected] can "Send As". It doesn't work. I tried to send an email to it via gmail and it failed and I tried to send an from it but it said that I don't have the "on behalf rights" (I've setup the "Send as" rights not the "on behalf of" ones...)
• as a shared mailbox. It almost worked. I does with [email protected] but not with [email protected]

Does anyone know how to achieve what should be a simple task?

Answer 1

I realized that when I create [email protected], it automatically tries to create an alias [email protected]. And this is why it fails. So I found the following workardound that works.

1. I create [email protected] and save
2. I edit [email protected] to delete the aliases (including [email protected] then) and update the email to be [email protected] and I save.