Diagnostic information for administrators: #550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found

Or, Diagnostic information for administrators: #550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##

NDR Error: Delivery has failed to these recipients or distribution lists

The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.

Possible Reason 1: - The user does not exist

Resolution: - Please check if the user email ID your typing is correct or not. Generally, this happens, if the user mailbox has been deleted or you are typing a wrong email ID

Possible Reason 2: - The user which have been deleted from your AD/Exchange, may still exist/added in some Transport Rules.

Resolution: - Please check all your Transport rules and delete the user email address from any transport rules that you have created under EMC > Organization Configuration > Hub Transport> Transport Rule

Cheers, please write me back if you have any query or feedback on this.

How to bypass clutter for all users in O365?

Or, Disabling clutter for all users in O365

Or, Creating ‘Bypass Clutter’ transport rule in MS O365

Descriptions: If you are looking for disabling clutter function for all currently active mailboxes in your O365 domain just for one time, you can disable clutter by following the KB http://www.techiessphere.com/2016/06/command-to-disable-clutter-for-single.html

But, If you want this clutter function to be bypassed for all current as well as upcoming users, you should create a transport rule for this.

Solution/Steps: Creating ‘Bypass Clutter’ transport rule in MS O365

Login to O365 Admin Portal > Go to Mail Flow > Create a New Trasport Rule as per the reference details are given in below screenshot

IMP Notes:

1. Set the message header 'X-MS-Exchange-Organization-BypassClutter' to the value 'true'

2. You may or may not need an exception in this rule, so you can skip that option if not required

Cheers, Please write me back if you have any query or feedback...