Sending, receiving, and organizing email in Outlook.com
Hello,
This does not necessarily mean that the address belongs to an existing Microsoft account. The username or part of it may be a reserved phrase that Microsoft’s automated registration system does NOT allow people to use.
When a phrase is reserved, the address cannot be registered, but there is also no account to sign in to or recover. That explains why registration says the address is unavailable while account recovery says the account does not exist.
Since unrelated usernames work, but multiple variations containing “esmailnouralden” are rejected, this strongly suggests that the exact name or part of it is being caught by Microsoft’s automated username filter. It may or may not specifically be the letters “mail,” and Microsoft does not publish its list of reserved or restricted username combinations.
Unfortunately, community members and regular support agents cannot view or override this filter. Microsoft also does not provide a public process for manually releasing a reserved Outlook.com username. The only available option is to submit feedback through Outlook.com > Help > Feedback, but there is no guarantee that the address will be reviewed or made available. Honestly it will be unlikely just to be honest with you. It is reserved for a reason.
You will most likely need to choose a variation that the registration system accepts.