Exchange Online NDR When the reoccurring outlook meeting is updated and sent

Hello aanandkarki ,

This issue occurs if the Clutter feature is enabled for the user but the Clutter folder is missing in the user’s mailbox.

To work around this issue, turn off Clutter for the user. To do this, use one of the following methods.

Method 1: Use Outlook on the web

1. In Outlook on the web, click Settings in the upper-right corner.
2. Click My app settings, click Mail, and then click Clutter.
3. Clear the **Separate items identified as clutter **check box, and then click Save.

Method 2: Use Exchange Online PowerShell

1. Connect to Exchange Online by using PowerShell. 

2. Run the following command:

Get-Mailbox user@contoso.com | Set-Clutter -Enable $false

Thanks,

Manu