Microsoft links Classic Outlook issue to email delivery problems

Microsoft is investigating a known issue that prevents some Classic Outlook users from sending emails via Outlook.com.

Affected users are being warned that their message hasn’t reached some intended recipients, and they will encounter this problem more often when the Outlook.com account they use to send email is an Outlook profile linked to another Exchange account.

“This message could not be sent. Try sending the message again later or contact your network administrator,” the non-delivery report (NDR) error displayed when sending or replying to emails reads.

“You do not have the permission to send the message on behalf of the specified user. Error is [0x80070005-0x0004dc-0x000524].”

Microsoft added that another condition that may trigger these errors is that the sender’s account has an Exchange Online mail contact with the same SMTP address.

​While investigating this issue and still looking for a fix, the…