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

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


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


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


  • 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

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

Manage Transport Rules

Transport rules

Configure your spam filter policies

Submitting spam and non-spam messages to Microsoft for analysis

Advanced spam filtering options

Spam email and Office 365 environment

Import-Mailbox fails occasionally

To import data from a .pst file, you must run the Import-Mailbox cmdlet from a 32-bit computer that has the following installed;

# 32-bit version of the Exchange management tools (download link : )
# Microsoft Office Outlook 2003 Service Pack 2 (SP2) or later versions

a few good articles ;

Check info:

1.      Please add parameter “-verbose” at the end of the Import-Mailbox and reproduce the issue, which can give us more info to narrow down the cause
2.      Is there any related error or warning event in the application log on the both client and exchange server?
3.    Make sure the mailboxes has been exported on the same version Outlook as you use on your import machine


1. Please make sure that outlook and any MAPI connections are closed prior to running the Import-Mailbox
2. Use outlook 2003 instead of outlook 2007 on the workstation if outlook is to remain open during the process
3. If using outlook 2007, ensure that outlook is logged in using the same credentials as the Import-Mailbox PowerShell window
4. Do not launch PowerShell under the “Run As” method. Instead log into Windows as the desired account with permission to the mailbox and launch PowerShell normally
5. If running Windows XP and getting the error: “PowerShell.EXE has encountered a problem and needs to close.  We are sorry for the inconvenience” – Make sure it dosent get connected to a READ-ONLY domain controller. It will not show up in the log of a XP computer, but trying the same on a Windows 7 and it will show that it connects several times during the import, but if it at one point hits a RODC, Powershell will crash. easy solution just add static entries for the domain to your hosts file.