# Outlook.com delivery problems

**URL:** <https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931>\
**Category:** uncategorized\
**Created:** [September 23, 2026, 10:25am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931 "2026-09-23T10:25:07Z")\
**Posts on this page:** 12\
**Page:** 1

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**Author:** ![MuckiSG](https://discourse.mailinabox.email/letter_avatar_proxy/v4/letter/m/e274bd/32.png) [@MuckiSG](https://discourse.mailinabox.email/u/MuckiSG)\
**Post date:** [September 23, 2026, 10:25am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/1 "2026-09-23T10:25:08Z")

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Hi,

i have problems to deliver emails to [outlook.com/Exchange](http://outlook.com/Exchange) online users and companies.mxtools shows DMARC and SPF are correct. When i press the mxtools “solve email delivery problems” button, i get 4 warnings but no error.  
mxtools offers a M$ Email delivery compliance check. DKIM, DMARC, SPF entries seem correct, only the status is red?!

 ![chrome_SpA8ENeEal](https://discourse.mailinabox.email/uploads/default/original/2X/e/e5f4c0cc871fbd7c598eb096b2fbf2c62229e0f0.png)

Unsubscribe is red, because i do not send newsletters, only standard email.  
Reputation is green.

Do you know these problems?

Thanks in advance,

Maurice

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**Author:** ![KiekerJan](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/kiekerjan/32/2339_2.png) [@KiekerJan](https://discourse.mailinabox.email/u/KiekerJan)\
**Post date:** [September 23, 2026, 2:55pm UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/2 "2026-09-23T14:55:17Z")

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> [@MuckiSG](#):
>
> i have problems to deliver emails to [Outlook.com](http://Outlook.com)

How do these problems surface? Are there errors in your logs? Are there reject mails, perhaps with an error message?

> [@MuckiSG](#):
>
> only the status is red?!

Without knowing what exactly the status checks, it is hard to come up with a reason. What exactly does this check? Is there an explanation?

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**Author:** ![andrew](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/andrew/32/1449_2.png) [@andrew](https://discourse.mailinabox.email/u/andrew)\
**Post date:** [September 23, 2026, 10:33pm UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/3 "2026-09-23T22:33:50Z")

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For tests with a little more detail, I found this helpful: https://dkimvalidator.com

And search these forums for “microsoft”. There is some good (though old) advice about convincing microslop to accept email from your server.

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<div class="post-metadata">

**Author:** ![MuckiSG](https://discourse.mailinabox.email/letter_avatar_proxy/v4/letter/m/e274bd/32.png) [@MuckiSG](https://discourse.mailinabox.email/u/MuckiSG)\
**Post date:** [September 24, 2026, 5:12am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/4 "2026-09-24T05:12:42Z")

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Dear Jan,

you are right, forgot the most essential. The rejecting mail says:  
"550 5.4.1  
Recipient address rejected: Access denied. "

Kind regards,

Maurice

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<div class="post-metadata">

**Author:** ![MuckiSG](https://discourse.mailinabox.email/letter_avatar_proxy/v4/letter/m/e274bd/32.png) [@MuckiSG](https://discourse.mailinabox.email/u/MuckiSG)\
**Post date:** [September 24, 2026, 5:16am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/5 "2026-09-24T05:16:20Z")

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Dear Andrew,

> [@andrew](#):
>
> [https://dkimvalidator.com](https://dkimvalidator.com)

DKIM & SPF passed, SpamAssassin score: 0.203

FYI,

Maurice

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**Author:** ![KiekerJan](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/kiekerjan/32/2339_2.png) [@KiekerJan](https://discourse.mailinabox.email/u/KiekerJan)\
**Post date:** [September 24, 2026, 8:57am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/6 "2026-09-24T08:57:03Z")

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> [@MuckiSG](#):
>
> "550 5.4.1  
> Recipient address rejected: Access denied. "

That specific message seems to mean the recipient does not exist ([NDR error code 550 5.4.1 "Recipient address rejected: Access denied" | Microsoft Support](https://support.microsoft.com/en-us/servicing/exchange/non-delivery-report/ndr-error-code-550-5-4-1-recipient-address-rejected-access-denied))  
Are you sure the email address is correct?

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<div class="post-metadata">

**Author:** ![MuckiSG](https://discourse.mailinabox.email/letter_avatar_proxy/v4/letter/m/e274bd/32.png) [@MuckiSG](https://discourse.mailinabox.email/u/MuckiSG)\
**Post date:** [September 24, 2026, 9:45am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/7 "2026-09-24T09:45:27Z")

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Hi Jan,  
yes the email address is correct and we hab das problem with another user from a different company in the near past.

The error code in a reject email for an non existing account is  
_550 5.5.0 Requested action not taken: mailbox unavailable_ (just tested it).

Thx 4 help,

Maurice

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<div class="post-metadata">

**Author:** ![KiekerJan](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/kiekerjan/32/2339_2.png) [@KiekerJan](https://discourse.mailinabox.email/u/KiekerJan)\
**Post date:** [September 24, 2026, 4:53pm UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/8 "2026-09-24T16:53:52Z")

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I assume the email address of your customer is reachable from other email providers? E.g. Gmail?

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<div class="post-metadata">

**Author:** ![andrew](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/andrew/32/1449_2.png) [@andrew](https://discourse.mailinabox.email/u/andrew)\
**Post date:** [September 24, 2026, 10:18pm UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/9 "2026-09-24T22:18:49Z")

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MS says 550 caused by SPF, DKIM, or DMARC issues. Perhaps this article will point you in the right direction.

[https://support.microsoft.com/en-us/outlook/fix-ndr-error-550-5-7-515-in-outlook-com](https://support.microsoft.com/en-us/outlook/fix-ndr-error-550-5-7-515-in-outlook-com)

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<div class="post-metadata">

**Author:** ![MuckiSG](https://discourse.mailinabox.email/letter_avatar_proxy/v4/letter/m/e274bd/32.png) [@MuckiSG](https://discourse.mailinabox.email/u/MuckiSG)\
**Post date:** [September 25, 2026, 6:32am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/10 "2026-09-25T06:32:02Z")

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Hi Andrew,

the 550 is a error with multiple reasons. Therefore you have the error code after the 550 like 5.5.0 or in my case 5.4.1. I think in the same direction with DKIM or DMARC but a test on mxtoolbox gives me green lights in the first place. Then i found the special test for [outlook.com](http://outlook.com) and hosted Exchange. Then i get the information from my initial post. Everything green but the status but i do not know what that means …  
The error you posted looks quite different to my problems.

Thx for help,

Maurice

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<div class="post-metadata">

**Author:** ![KiekerJan](https://discourse.mailinabox.email/user_avatar/discourse.mailinabox.email/kiekerjan/32/2339_2.png) [@KiekerJan](https://discourse.mailinabox.email/u/KiekerJan)\
**Post date:** [September 25, 2026, 8:35pm UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/11 "2026-09-25T20:35:06Z")

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I tried this test [Microsoft Email Delivery Compliance](https://mxtoolbox.com/mxtips/microsoft_compliance)  
Is that the one you mean? It didn’t like my mail either, so try this one first: [learndmarc.com](http://learndmarc.com)

Also look at Microsoft tools [Smart Network Data Services](https://substrate.office.com/ip-domain-management-snds/SNDS) and see if there’s a report on the ip you use

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<div class="post-metadata">

**Author:** ![MuckiSG](https://discourse.mailinabox.email/letter_avatar_proxy/v4/letter/m/e274bd/32.png) [@MuckiSG](https://discourse.mailinabox.email/u/MuckiSG)\
**Post date:** [September 30, 2026, 10:02am UTC](https://discourse.mailinabox.email/t/outlook-com-delivery-problems/16931/12 "2026-09-30T10:02:36Z")

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Hi Jan,

i tried you suggested platform and all tests are passed. I am going to check the M$ page aswell.

Thx,

Maurice