Office365 Recipient address rejected: Access denied

Funny thing happend……

For some reason new email accounts (older then 24 hours) and email aliases was not working properly within Office365.

External contacts was reporting:

tried to deliver your message, but it was rejected by the server for the recipient domain mydomain by mydomain.mail.protection.outlook.com

550 5.4.1 [<username>@<mydomain>]: Recipient address rejected: Access denied

Reason:

  • Accounts was is getting propagated in an accepted time frame (24 hours)

Issue:

  • ¬†The affected accounts is unable to receive email from external contacts – emails are not getting delivered.

Resolution:

  • We changed the accepted domain to Internal relay to resolve the issue.
  • As a precaution we enabled Conditional Sender ID and NDR backscatter to avoid spam attacks.

Articles on Mail Flow for reference:

Exchange Online Protection Limits

https://technet.microsoft.com/en-in/library/exchange-online-protection-limits.aspx

How Office 365 does SPF checks for customer-to-customer mail

http://blogs.msdn.com/b/tzink/archive/2015/02/26/how-office-365-does-spf-checks-for-customer-to-customer-mail.aspx

Manage Transport Rules

http://technet.microsoft.com/en-us/library/jj657505(v=exchg.150).aspx

Transport rules

https://technet.microsoft.com/en-IN/library/jj919238(v=exchg.150).aspx

Configure your spam filter policies

http://technet.microsoft.com/en-us/library/jj200684(v=exchg.150).aspx

Submitting spam and non-spam messages to Microsoft for analysis

http://technet.microsoft.com/en-IN/library/jj200769(v=exchg.150).aspx

Advanced spam filtering options

http://technet.microsoft.com/en-us/library/jj200750(v=exchg.150).aspx

Spam email and Office 365 environment

http://blogs.technet.com/b/exchange/archive/2014/07/25/spam-email-and-office-365-environment-overview.aspx