Remote server returned '554 5.7.0 < #5.7.520 smtp;550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)>'

Question

Remote server returned '554 5.7.0 < #5.7.520 smtp;550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)>'

Linda Roberts 20

I have tried many times to send my group email and it is coming back as undeliverable.

What can I do to correct this issue?

Thank you

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Answer accepted by question author

EmilyS726 272.5K Independent Advisor

Looks like the recipient's side is flagging your email as spam.

Are you the outlook.com user who tried to send the email to a non-outlook user, or are you a non-outlook user trying to send an email to outlook.com user?

It sounds like you are sending it to a group of users?? Try to send to just one person, see if it goes through.

Linda Roberts 20 Reputation points

2026-01-17T21:37:57.91+00:00

I did that and it was returned undeliverable as well.
Linda Roberts 20 Reputation points

2026-01-17T21:38:23.0633333+00:00

I am an outlook user sending to non-outlook users.
EmilyS726 272.5K Reputation points Independent Advisor

2026-01-17T21:51:05.91+00:00

Try to send the email in non-html format, and see if it helps.

Instruction can be found here: https://support.microsoft.com/office/change-the-message-format-to-html-rich-text-format-or-plain-text-in-outlook-338a389d-11da-47fe-b693-cf41f792fefa

1 additional answer

Your answer

Linda Roberts 20 Reputation points

2026-01-17T21:37:57.91+00:00

I did that and it was returned undeliverable as well.
Linda Roberts 20 Reputation points

2026-01-17T21:38:23.0633333+00:00

I am an outlook user sending to non-outlook users.
EmilyS726 272.5K Reputation points Independent Advisor

2026-01-17T21:51:05.91+00:00

Try to send the email in non-html format, and see if it helps.

Instruction can be found here: https://support.microsoft.com/office/change-the-message-format-to-html-rich-text-format-or-plain-text-in-outlook-338a389d-11da-47fe-b693-cf41f792fefa

Answer 1

Linda Roberts 20

Undeliverable: Fw: Weekly Contact

******@outlook.com

You

Delivery has failed to these recipients or groups:

Linda Roberts Your message wasn't delivered because the recipient's email provider rejected it.

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