5.7.520 Message blocked because it contains content identified as spam. AS(4810)

Copper Contributor


My outlook this afternoon suddenly decided to stop working properly.  I have 2 outlook emails neither of them are sending emails with attachments.  I can't even send one to myself without it being rejected.  There is no admin person to refer to.  What is going on?  

The messages get sent back with:

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

Diagnostic information for administrators:

Generating server: SE2P216MB1965.KORP216.PROD.OUTLOOK.COM

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

Original message headers:


I've taken out the email address I was trying to send to which was written under Generating Server.


I have had a look at other community forums and cannot find a resolution.


33 Replies
I can send emails with attachments via my phone outlook app just not my laptop!



Im getting the same thing. It will let me send a jpg as an attachment but not a PDF file

how do you get the help to resolve this. I found a number to call but as soon as they found out it was for a personal email i got sent back here. I use a personal email for my business.
Im the same, use my personal email for work. No idea how to resolve. Hence how I found myself here as well. Hoping someone will jump on and give us both a solution...

@losingthewilltolive I am also having the same problem.  I can send pictures, but no pdf on my computer.  My cell phone yes, I can send pdf.  I think the server on microsoft is buggy.  I see the problem with others, are around the same time. Hopefully Microsoft will fix their server problem.  


I chat with microsoft, they said it was a problem on their end. They are working on fixing the issue. Here is where I had the chat and gave them my email address, so they can fix it and keep me informed.

Contact Us - Microsoft Support

@losingthewilltolive  I am having the same issue all emails being returned! microsoft please help!!!!!!! 

Same here. Does not allow PDF or OpenDocument files to go through. Sent as xls and all good.

Same here! I'm getting the same issue. I thought it was just me and have tried numerous different things, hopefully Microsoft resolves soon @losingthewilltolive 

Same over here,
Somebody knows a solution ????

I'm another one who has fallen victim. My PDF attachments are no longer being received—png files are fine.

Ik heb hetzelfde probleem, ben blij dat ik op dit forum gestuit ben. Kon mijn facturen al niet verzenden naar mijn opdrachtgevers :(

Same problem here, only via laptop, not via mobile device. With PDF docs 

@BusMus ja voor mij hetzelfde. Nog nooit meegemaakt. Zodra ik een pdf bestand toevoeg krijg ik een mail terug met deze melding.

De belangrijkste vraag is, hoe kan ik dit oplossen of hoe word dit opgelost?


Het is een bug in de update van Outlook. Het is vaker voorgekomen, zodra ze de update fixen komt het goed. Even geduld en een omweg zoeken.

Als ik mijn mail incl bijlage als concept op sla, dan open ik het via de mobiele app en verstuur ik mijn mail incl bijlage pdf via mijn mobiel.

I can't attach PDF files in hotmail.com as of today with the same error messages.



Top dankjewel voor de tip!

Voor nu kan ik alleen maar wachten totdat er een update komt vanuit Outlook?



Exactly same problem - all message containing PDF are returned with this error message.

I hope Microsoft would fix this very quickly.

It is a bug, they are working on it to get fixed. For now, i found a way to work around this problem. Save your mail with the pdf attachement as a concept. Afterwards go in with your mobile device to send it from there.