Multiple Objects with Sid

Error description:

An error occurred when you tried to access your mailbox because a server with information about you and your mailbox couldnt be found.

Request
Url: https://cas.heerwegh.com:443/OWA/
User host address: ........
OWA version: .........

Exception
Exception type: Microsoft.Exchange.Data.Directory.Recipient.NonUniqueRecipientException
Exception message: Multiple objects with Sid S-1-5-XXXXXXXXXXXXXXXXXXXXXXXXXXX were found

Solution:

The problem here is that the msExchangeMasterAccountSid value has been set one more than one object.

Run these commands to export the list of SID's and MsExchMasterAccountSid to quickly find out the conflicting object(s)

Import-module activedirectory

Get-ADUser -SearchBase "OU=Users,DC=heerwegh,DC=com" -filter * -Properties objectsid,msexchmasteraccountsid | Select alias,msexchmasteraccountsid,objectsid | Out-GridView