Forum Discussion
Remote Server returned '550 5.7.501 Access denied, spam abuse detected.
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
MicrosoftChanging the primary SMTP to a vanity domain will solve this issue for sure :)
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-a0c9-df85bf8533c3
5.7.501
Access denied, spam abuse detected
The sending account has been banned due to detected spam activity.
For details, see https://support.office.com/en-gb/article/Fix-email-delivery-issues-for-error-code-451-57500699-ASxxx-in-Office-365-51356082-9fef-4639-a18a-fc7c5beae0c8.
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-ASxxx-in-Office-365-51356082-9fef-4639-a18a-fc7c5beae0c8
- Victor_Ungureanu
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 :)