Forum Discussion
How to add and grant access to external users for an M365 mailbox
Hello, what is the workaround to allow external users to share a mailbox?
External users who are not within our domain should be able to send and receive emails using an address like (email address removed for privacy reasons). I have tried setting up both Shared and Group mailboxes, but it’s not possible to add external members, even after creating and inviting the external user in Entra and granting them access as a Guest or Member. These external users need to be able to log in to this mailbox to send and receive emails.
As of now, it seems impossible to add or delegate external members. We do not require Teams or any other apps; we only need email/Outlook services.
I have attempted multiple configurations, but nothing seems to work.
Please provide information about how you were able to allow external users sign into a mailbox created in your Microsoft 365 tenant.
From your statement "These external users need to be able to log in to this mailbox to send and receive emails.": the feasible setting is to allow external users send and receive emails with a "mailbox" created in your tenant but they won't be able to sign into the mailbox. The external users will receive emails sent to the email address into their primary inboxes and will be able to send emails to the email address from their mailboxes.
The Microsoft 365 group enables both external and internal users membership but none is able to sign into the mailbox as it does not have a shareable password.
Thanks.
- No such thing, mailboxes can only be accessed within the confines of the same tenant. You can forward the messages to an external address, but cannot give an external user direct access to a mailbox.
- OK thanks for confirming.
