Hi,
we have a problem with an external user.
The company of the user changed the mail of all users in their company.
When user from our company send emails to the external user's new email address, the emails are send to his old email address.
His old email address is not existing anymore and therefore the postmaster sends a mail, that the mail couldn't be delivered.
In the postmaster mail it says: "The message you sent to <old email> couldn't be delivered due to: Recipient email address is possibly incorrect.
When we look in our "Sent Items" Folder in Outlook we can see the mail with the new email address of the user.
But the postmaster mail includes the old email address.
I isn't a user specific problem in our company.
When I sent my first mail to the new address of the external user from my own mailbox, I got the message from the postmaster too and the mails haven't reached the external user.
But the external user can send emails to users of our company.
The email addresses are not saved in ECP or local AD.
The only thing that is saved is the contact info of the B2B guestuser of the old email in Azure AD.
There is the old email as the primary email and the new email as the alternate email.
The proxy address is also the new email address.
Any ideas?
Is it even a problem at our company?
Thanks