Remote server returned 550 5.7.520

Jipe 20 Reputation points
2025-06-24T13:16:11.5566667+00:00

Bonjour depuis vendredi (4jours),

j'ai ce message :

Remote server returned '550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)'

pour quasiment tous les mails que j'envoie, c'est très pénible, j'utilise aussi bien l'application de bureau Outlook que la version sur navigateur.

Aidez moi svp

Outlook | Windows | Classic Outlook for Windows | For business
0 comments
Answer accepted by question author
Jayden-P 26,210 Reputation points Microsoft External Staff Moderator
2025-06-24T14:05:28.77+00:00

Hi @Jipe

Thank you for posting your question in the Microsoft Q&A forum. 

Based on the information you have provided, looks like you cannot send emails with PDF attachments.

I am so sorry about the inconvenience you are facing. We have received some reports about this known issue. This error means you send emails with some types of attachments (such as PDF)

To resolve the root cause of this issue, you need to contact MS support team, they will collect logs and data and troubleshoot from the backend.

You can raise ticket via Outlook or in Admin Center.

User's image

User's image

Meanwhile, you can try this work around in the picture below.

User's image

If you are sending a PDF file, please convert it to PNG or JPG then send the email.

Since this bug doesn't affect mobile device, you can draft an email on your computer, then send it with your phone. It will be delivered successfully.

Once again, I apologize for the inconvenience this might cause you. I totally understand how frustrating and time consuming this would be for you.

We will try our best to resolve this issue to enhance customers' experience.

Thank you for your understanding.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.User's image

Was this answer helpful?

0 comments

2 additional answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Jipe 20 Reputation points
    2025-06-25T09:37:23.6633333+00:00

    The problem still hasn't been solved for me, despite your intervention.

    Outlook has been blocking the sending of attachments since the last update last week.

    I've checked that my email wasn't suspected of being spam on mxtoolbox.

    If there are no attachments it works and I have used the old version of Outlook Classic and that works too.

    Was this answer helpful?

  2. Jipe 20 Reputation points
    2025-06-24T14:25:48.4933333+00:00

    thanks, but the problem dont solve itself, i sent a feedback to support team.

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.