How to unblock my email address so I can send email in MS365 outlook

Question

How to unblock my email address so I can send email in MS365 outlook

Leonard Bliss 0

How to unblock my email address so I can send email in MS365 outlook.

I sent an email to just over 200 recepients and it failed to send and now blocks all my sent emails. I can receive but not send. Other people on the same domain are not affected and can send and receive email. What did I do wrong and how do I correct it?

Thanks!!!!!

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Answer 1

SokiGuo-MSFT 31,541 Microsoft External Staff

Hi @Leonard Bliss

Welcome to our forum!

Based on your description, it looks like you've sent emails to a large number of recipients. It is likely that it was automatically blocked by being identified as spam.

Are there any error messages? Try sending emails to only a small number of users at once to check if there are any discrepancies.

To unblock you, you'll need to contact your recipient to add you to your safe list.

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Leonard Bliss 0 Reputation points

2024-12-10T14:26:47.25+00:00
Delivery has failed to these recipients or groups:

[******@xxx.com] This message couldn't be delivered because the sending email address was not recognized as a valid sender. The most common reason for this error is that the email address is, or was, suspected of sending spam. Contact the organization's email admin for help and give them this error message.

Diagnostic information for administrators:

Generating server: CO1P222MB0322.NAMP222.PROD.OUTLOOK.COM

******@xxxx.com Remote server returned '550 5.1.8 Access denied, bad outbound sender AS(42004)'

Original message headers:

Received: from CO1P222MB0322.NAMP222.PROD.OUTLOOK.COM ([fe80::3240:c876:ab79:1c5f]) by CO1P222MB0322.NAMP222.PROD.OUTLOOK.COM ([fe80::3240:c876:ab79:1c5f%4]) with mapi id 15.20.8251.008; Tue, 10 Dec 2024 14:23:25 +0000 MIME-Version: 1.0 Content-Type: text/plain Date: Tue, 10 Dec 2024 14:23:25 +0000 Message-ID: <******@CO1P222MB0322.NAMP222.PROD.OUTLOOK.COM> Subject: test 23

Reply__Forward

RS
Leonard Bliss 0 Reputation points

2024-12-11T18:37:55.1633333+00:00

I cannot send to anyone. I cannot send using webmail either
SokiGuo-MSFT 31,541 Reputation points Microsoft External Staff

2024-12-12T01:44:42.5266667+00:00

Hi @Leonard Bliss

It looks like the email address was flagged as a risk sender, which caused the email to be rejected. This typically happens when the email server suspects that the address was used to send spam.

Here's what you can do:

Contact your email administrator: The administrator can check the email server's reputation and settings to find out why the address was flagged.

Check email content: Sometimes, emails can be flagged if they contain certain keywords or patterns typical of spam. Review your email content to ensure it doesn't trigger spam filters.

Authentication: Make sure that your email system is properly authenticated with SPF, DKIM, and DMARC settings. These protocols help ensure that your emails are legitimate and not spoofed.
SokiGuo-MSFT 31,541 Reputation points Microsoft External Staff

2024-12-17T01:54:18.12+00:00

Hi @Leonard Bliss

Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back. If you think my reply is helpful to you, please remember to mark it as an answer. Warm thanks.

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How to unblock my email address so I can send email in MS365 outlook

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