Hotmail or Outlook.com rejects or delays your e-mails: reading the message that comes back

E-mail·· 3 views· 4 min read

The short answer: when Microsoft will not accept a message for a Hotmail or Outlook.com address, you get a notice back from our server. There are two kinds: a permanent refusal (the code starts with 5), where the message will not be delivered, and a deferral (the code starts with 4), where the server keeps retrying by itself for a while. The text Microsoft adds to the code almost always says why: that is the line worth reading.

How to read the notice

What the notice says What it means
A code starting with 5, and the address does not exist or is disabled The address is mistyped or the account was closed. Check it with the person. See the 550 error and its variants.
A code starting with 5, mentioning a block, reputation or policy Microsoft refused because of the sender: the sending IP, the domain, or authentication. Do not keep resending: fix the cause first.
It mentions authentication, SPF, DKIM or DMARC Your domain did not pass the check: SPF, DKIM and DMARC.
A code starting with 4, or “delivery is delayed” A temporary deferral. Our server tries again; it only gives up if the deferral continues, and then it tells you.
The recipient’s mailbox is full The problem is on the recipient’s side. Let them know some other way.

What to do with the notice in hand

1 Open the notice and find the part that comes from Microsoft’s server: the code and the sentence with it. It often includes a reference or a link to a Microsoft support page for senders.
2 Follow the message’s path in cPanel under Track Delivery: it shows whether it left, where it went and what the other side answered. See Track Delivery.
3 If it mentions authentication, open Email Deliverability in cPanel and fix SPF and DKIM; then check DMARC: the deliverability panel.
4 If it mentions the IP or reputation, check whether the domain or IP is on a blacklist. On a shared hosting plan the sending IP is the shared server’s: open a ticket with the message that came back and we check it. On a VPS or dedicated server the IP is yours, and reverse DNS counts too: PTR and reverse DNS.
5 If it is a deferral, wait: the server retries without you doing anything. If it keeps happening with Microsoft, or ends in a refusal, open a ticket.
6 When you open the ticket, send the full notice (not just the summary), the destination address and the time you sent it.
Do not resend the same message over and over after a reputation refusal. Each refused attempt counts against the sender and can widen the block. Fix the cause and send once.
If you run your own server (VPS or dedicated), get to know the programmes Microsoft offers senders, where you follow the IP’s reputation and ask for a block to be reviewed. Find them on Microsoft’s official page for senders.

Got a notice from Microsoft and cannot see why? Send us the full notice.

Open a support ticket

SEE ALSO

Bounce message 550: user unknown, relay denied and rejected, what each one means

Track Delivery: finding out what happened to a message you sent

SPF, DKIM and DMARC: why your e-mail lands in spam

Your domain or IP is on a blacklist: how to check and how to get off it

Why your e-mail is not sending or receiving

Your e-mails land in Junk at Hotmail and Outlook.com: what the sender can check

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