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All emails sent to emails with a yahoo domain are getting returned as undeliverable. "Remote server returned '550 5.4.300 message expired -> 451 [RL01] Message temporarily deferred,"

Anonymous
2024-01-15T05:12:54+00:00

Any emails I send from my microsoft account (via Outlook) to yahoo emails get returned as undeliverable. Similarly, any emails my wife sends from HER email address (same microsoft account) to a number of idifferent domains (incl. yahoo, gmail, and others) are being returned undeliverable. This is really causing a problem for our business. This is happening whether we send from our email in office.com or from our OUtlook application. It is also happening on both MAC and PC. Please advise

Here are some of the messages with the undeliverable messages:

"Server at ********************** returned '550 5.4.316 Message expired, connection refused(Socket error code 10061)'"

"Remote server returned '550 5.4.300 message expired -> 451 [RL01] Message temporarily deferred,"

 "Server at ********************** ( **********************) returned '421 4.4.2 Connection dropped due to SocketError'

"1/12/2024 1:49:04 AM - Server at DS0PR15MB5624.namprd15.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
1/12/2024 1:40:58 AM - Server at ********************** returned '421 4.4.2 Connection dropped due to SocketError'

"Server at********************** returned '450 4.4.316 Connection refused [Message=Socket error code 10061] [LastAttemptedServerName=**********************] [LastAttemptedIP=**********************] [SmtpSecurity=-2;-2] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* 2024-01-12T20:39:52.395Z 08DC0841E017BFE6'

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  1. Anonymous
    2024-01-23T15:43:08+00:00

    I was having the same issue. Messages sent to yahoo would be appear to be sent, but after about 24 hours time out, senders would receive a NDR error message 550 5.4.300 Message expired.

    This was happening to all 3 of my O365 tenants. All of them had SPF and DMARC configured for the domains, but not DKIM.

    After configuring DKIM on each of the tenants, messages sent to yahoo were delivered.

    So t appears to be related to the newly implemented security requirements for Yahoo mail servers. The changes were supposed to happen February 2024, but it seems Yahoo started a little early.

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  2. Anonymous
    2024-01-21T12:41:52+00:00

    I'm having the same issue - see error below.

    1. I can send to my yahoo.com account from a gmail account
    2. I have 3 outlook accounts with different domains. All 3 outlook accounts cannot send to my yahoo.com account. It is hard to believe all 3 outlook unrelated domains were blacklisted in 1 day.

    I think the issue is Outlook/MS

    Here is the ERROR received in OUTLOOK

    1/21/2024 12:22:26 PM - Server at DS7PR20MB4759.namprd20.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'

    1/21/2024 12:04:03 PM - Server at mta6.am0.yahoodns.net (67.195.204.74) returned '421 4.4.2 Connection dropped due to SocketError'

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  3. Anonymous
    2024-01-18T18:29:54+00:00

    We are having the exact same issue and have tried to resolve with no avail. Please advise

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    5 people found this answer helpful.
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  4. Anonymous
    2024-01-21T22:18:41+00:00

    I am having the same issue. It appears that there are quite a few of us. Just wondering how long does it usually take for someone to respond and work on the issue?

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  5. Anonymous
    2024-01-19T15:25:08+00:00

    If it is a "backend-side issue" does that mean that MS is likely on the file working to fix it for all of us? Or do we have to contact customer support in order to get a solution?

    I say that because we have a charitable organization account and I don't know if we get tech support with that or not since we aren't a paying customer.

    We are also experiencing this issue. Any email from all of our employees (4) sent to any yahoo owned email (yahoo.co.uk, yahoo.fr, yahoo.com, yahoo.ca, ymail.com, etc.) plus we have received errors from aol.com accounts as well. I personally have received 24 such reports, starting on January 12 - the same date noted in the original help request. (Which lends weight to it being a problem with yahoo/aol or MS in my mind. Some setting must have been changed.)

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