Remote Server returned '550 5.7.501 Access denied, spam abuse detected.

[Anthony Obi]

Anyone else receiving "Remote Server returned '550 5.7.501 Access denied, spam abuse detected." when attempting to send from @<O365subdomain>.onmicrosoft.com?

Found various discussions that mention MS Engineers 'delisting' domain to resolve the issue?

http://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook/remote-server-returned-550-57501-...

http://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook-mso_win10/cant-respond-to-emails-...

http://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook/remote-server-returned-550-57501-...

[#2]

Yes, this is something usual when sending from onmicrosoft.com and when the originating IP is from specific network classes.

You can send from a vanity domain, or send from another network that is not blacklisted, or you can open a service request to Microsoft Support and give them a complete NDR.

[#3]

Thanks Victor.

Attempting to send from https://outlook.office.com so assuming no way of affecting/changing the originating IP network classes etc?

Will try applying custom domain (vanity domain) to O365 tenancy and try resending.

(Failing that, service request to Microsoft Support as suggested)

Thanks

[#4]

Changing the primary SMTP to a vanity domain will solve this issue for sure 🙂

[#5]

Also found list of NDR Codes from O365

https://support.office.com/en-gb/article/Email-non-delivery-reports-in-Office-365-51daa6b9-2e35-49c4...

5.7.501

Access denied, spam abuse detected

The sending account has been banned due to detected spam activity.

For details, see Fix email delivery issues for error code 451 5.7.500-699 (ASxxx) in Office 365. Verify that any account issues have been resolved, and reset its credentials. To restore this account’s ability to send mail, contact support through your regular channel.

https://support.office.com/en-gb/article/Fix-email-delivery-issues-for-error-code-451-5-7-500-699-AS...

[#6]

When sending from the onmicrosoft.com domain the cause of the NDR is most likely not that "The sending account has been banned due to detected spam activity."

As I said before, sending from the onmicrosoft.com domain is blocked when the originating IP is part of specific IP classes as a measure of preventing spammers to create free trial tenants and sending spam using them 🙂

[#7]

@Anthony Obi 

I am getting same error whenever I send any mail to any one (Inside the group or outside the group).

Please help me.

Delivery has failed to these recipients or groups:

o365su12@microsoft.com
Your message wasn't delivered because the recipient's email provider rejected it.

Diagnostic information for administrators:

Generating server: BM1PR01MB2561.INDPRD01.PROD.OUTLOOK.COM

o365su12@microsoft.com
Remote Server returned '550 5.7.501 Service unavailable. Spam abuse detected from IP range. For more information please go to http://go.microsoft.com/fwlink/?LinkId=526653. S(2017052602) [BM1PR01MB2532.INDPRD01.PROD.OUTLOOK.COM]'