Microsoft fixes Classic Outlook bug that blocked some email sends
Microsoft has rolled out a server-side fix for a recent Classic Outlook problem that prevented some users from sending messages through Outlook.com. The issue caused non-delivery warnings and error codes for affected accounts, and the company says the change has been in production as of April 3, 2026. What happened Some Classic Outlook users received non-delivery reports (NDRs) with error codes such as 0x80070005-0x0004dc-0x000524 and the message: "This message could…