Why is my emails being rejected when sent?

Question

my sent emails are being rejected by all recipients. outlook, gmail etc.

it doesn't seem to matter if they have a body of message in them or empty etc

I run a small photography business so I do receive and send email quite frequently, some emails have clients final images on them some have a link to their viewing gallery etc.

how do I fix this.

Answer 1

Hello

Are you using a free outlook.com/hotmail.com address, or is this a business email address, with your own domain, or with the onmicrosoft.com domain?

Can you 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:

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

Outgoing messages being rejected for all recipients usually means either:

1. The messages are being blocked as spam/abuse
2. There is a delivery/non‑delivery problem on the recipient side

For Outlook.com / Outlook on the web, use these checks and fixes:

1. Check the non‑delivery report (bounce message)
   Open one of the “delivery failed” messages and read the error text:
   • If it mentions “blocked”, “listed in”, or references sites like spamcop, dynablock, blackhole, spamhaus: your account or sending IP is being treated as a spam source by the recipient’s server. In that case, the guidance is:
     • Contact the recipient’s email provider support and request that the account or domain be unblocked.
2. Confirm the basic causes listed in Outlook.com guidance
   From the Outlook.com help:
   • Verify the recipient addresses are valid and typed correctly.
   • Check if the recipient’s mailbox is full or their server is having issues (this will usually be stated in the bounce).
   • If the error mentions spam filters, the message is being blocked as spam by the recipient’s server.
3. Check attachment size and content
   • Outlook.com cannot send messages with attachments larger than 25 MB. If photography files are large, reduce size or use a cloud link instead. Oversized messages may fail to send or be rejected.
4. If you get a non‑delivery receipt but the address is correct
   • Use the dedicated Outlook.com sender support flow: follow the steps under Sender Support in Outlook.com in the “Can’t send mail in Outlook.com” article. This is specifically recommended when messages to valid addresses bounce.
5. New or low‑reputation Outlook.com account
   • If the Outlook.com account is relatively new or has recently increased sending volume (for example, more client mail with links and images), Outlook.com may temporarily enforce a low sending quota or stricter filtering until reputation improves. This can contribute to rejections on some destinations.
6. Ask recipients to safelist the address
   • Have key clients add the business email address to their safe senders list and contacts. This can help prevent spam‑filter‑based rejections on their side.
7. If all else fails
   • Use the error text from the bounce as the starting point and follow the specific reason given (invalid address, mailbox full, spam/blacklist, etc.), as outlined in the Outlook.com delivery‑failure guidance.

If the bounce messages show specific error codes or text (for example “blocked”, “listed in”, or a particular blacklist name), use that wording when contacting the recipient’s provider or Outlook.com sender support so they can review and unblock.

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References:

• Sent email in Outlook.com comes back "delivery failed"
• Can't send or receive email in Outlook.com