issue with sending email in outlook giving following error code : cf24

I am having the same issue that just started on Tuesday, February 20, 2024.

I can login to my Gmail account and send emails without an issue.

Here are the error codes from the undeliverable messages.

Technical details

MessageDeliveryFailedException: Could not deliver the message [len=70, data=000000009A25727315463047823F9CCD733FC28507000552D3DCD214C14FA177361D98A4134D00000000010F00000552D3DCD214C14FA177361D98A4134D0000127AFC770000] sent at 2/19/2024 9:32:56 PM. Failure code: 21be

Technical details

SmtpSubmissionPermanentException: Smtp submission failed. Server 'smtp.gmail.com' Port '587'. --> Unexpected SMTP server response. Expected: 235, actual: 334, whole response: 334 eyJzdGF0dXMiOiI0MDAiLCJzY2hlbWVzIjoiQmVhcmVyIiwic2NvcGUiOiJodHRwczovL21haWwuZ29vZ2xlLmNvbS8ifQ==

Failure code: cf24

SmtpSubmissionPermanentException: Smtp submission failed. Server 'smtp.gmail.com' Port '587'. --> Unexpected SMTP server response. Expected: 235, actual: 334, whole response: 334 eyJzdGF0dXMiOiI0MDAiLCJzY2hlbWVzIjoiQmVhcmVyIiwic2NvcGUiOiJodHRwczovL21haWwuZ29vZ2xlLmNvbS8ifQ==   Failure code: cf24

Technical details SmtpSubmissionPermanentException: Smtp submission failed. Server 'smtp.gmail.com' Port '587'. --> Unexpected SMTP server response. Expected: 235, actual: 334, whole response: 334 eyJzdGF0dXMiOiI0MDAiLCJzY2hlbWVzIjoiQmVhcmVyIiwic2NvcGUiOiJodHRwczovL21haWwuZ29vZ2xlLmNvbS8ifQ==   Failure code: cf24

I am having the same issue with a BT email account. All messages bounce back in New Outlook but not in Outlook (old)

Technical details

SmtpSubmissionPermanent5XXException: Smtp submission failed. Server 'mail.btinternet.com' Port '465'. --> Unexpected SMTP server response. Expected: 235, actual: 535, whole response: 535 invalid user ID or password from 52.98.150.29

Failure code: cf24

Hi all,

The problem is ONLY on the NEW Outlook. Revert back to the old one and there is no problem. They are now aware of this issue.

The new version unexpectedly went down for a bunch of people about a week ago. We are all having the isue about receiving ok but not sending. MS is aware of the problem since another person on this thread contacted them. For now the classic version sends. I test the new version every day to see if the issue is fixed yet. I'm no a mac so went to apple mail till the issue gets resolved. No idea how long that may take.

I have exactly the same with Gmail on business outlook

Every email sent bounces back.

Thanks.