Hotmail not reaching new recipients

If Hotmail messages are not reaching new recipients, the most common causes in the provided guidance are sender-side delivery restrictions rather than anything the recipient changed in contacts or trusted sender settings.

Relevant causes include:

1. The recipient’s server rejected the message Outlook.com notes that non-delivery receipts usually include the reason. Common reasons include:
   • invalid recipient address
   • recipient mailbox full
   • recipient server issues
   • spam filtering on the recipient side
2. The sending side may have a temporary sending restriction Newly created Outlook.com accounts can have a lower temporary sending quota until credibility is established.
3. The message may be affected by message content or formatting Outlook.com specifically notes that:
   • attachments larger than 25 MB cannot be sent
   • an email signature can sometimes affect sending, and removing the signature and resending may help
4. Recipient-side allow lists do not always override server-side blocking Safe sender or trusted sender settings help with junk filtering, but if a message is blocked before delivery because of sender reputation or authentication issues, that recipient setting may not be enough.
5. Sender reputation or authentication problems can block delivery The provided support guidance and Q&A examples show that messages can be rejected because the sender’s mail server or sending IP has a poor reputation, is on a block list, or does not meet authentication requirements. In those cases, the fix is on the sender’s mail provider or sending system, not in the recipient’s trusted sender list.

What to check:

1. Review any non-delivery receipt for the exact error.
2. If the message has an attachment, make sure it is under 25 MB.
3. Remove the email signature and try again.
4. Make sure the recipient address is correct.
5. If the error indicates blocking, spam reputation, or authentication failure, use Sender Support in Outlook.com or have the sending provider investigate.
6. If the recipient is using Outlook.com, having them add the address to Safe senders may help only when the message is reaching their mailbox filtering stage.

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