email with attachments

Question

I can receive emails from my mum, but as of this afternoon when she sends an email back with an attachment it shows her a message saying undeliverable blocked as possible spam? Can anyone help please?

Answer 1

Hello

Can you see if your mom can send the email in plain text -

Use the instruction here, change the email to plain text or rich text format (basically avoid the html format) and see if it goes through. It has to be done on the computer though, not on phone.

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 2

When attachments suddenly start getting blocked as spam in Outlook.com, the issue is usually on the sending side (your mum’s account) or due to Outlook.com’s spam/attachment filters.

Try these steps in order:

1. Ask your mum to check the attachment
   • Make sure the total attachment size is under 25 MB. Outlook.com cannot send messages with attachments larger than 25 MB.
   • Check the file type. Certain file types (for example, .exe or some database files) are blocked for safety. If she is sending one of these, have her:
     • Upload the file to OneDrive and send a link instead, or
     • Compress it into a .zip file, or
     • Rename the file extension to something allowed (for example, from file.exe to file.docx), send it, then after downloading, rename it back on the receiving side.
2. Check if this is a known Outlook.com issue
   • There has been a known issue where outgoing emails with attachments from Outlook.com accounts were incorrectly treated as spam and blocked. In such cases, the sender may need to contact Microsoft support from their account, as this is handled on the service side and not something that can be fixed from the recipient’s mailbox.
3. Add each other as trusted contacts
   • Ensure your mum’s email address is in the Outlook.com Contacts list.
   • Ask your mum to add the recipient address to her Contacts as well.
4. Use Safe Senders
   • On the recipient side, add your mum’s address to the Safe senders list in Outlook.com so messages from her are less likely to be treated as spam.
5. If a non-delivery report (NDR) is shown
   • The NDR usually includes the reason (for example, spam filters). If the address is correct and the NDR still appears, the sender can use Outlook.com Sender Support to investigate further.

If none of the above helps and the problem persists only when there is an attachment, the sender should contact Outlook.com support, as this matches the pattern of the known bug where some users’ outgoing messages with attachments are incorrectly blocked as spam.

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References:

• Can't send or receive email in Outlook.com
• Blocked attachments in Outlook
• Outlook blocked access to the following potentially unsafe attachments
• Outgoing emails with attachments undelivered as spam - Microsoft Q&A