How to remove auto-mapping in Exchange 2010

I took the following steps on our Domain Controller server to remove the auto-mapping feature.
1. Open the tool ‘ADSI Edit’ from the Administrative Tools.
2. Browse to the offending user(mailbox) that you would no longer like to be automatically mapped to particular users.
3. Right-click the account and select Properties.
4. In the Attribute Editor, select ‘Filter’ in the bottom right corner.
5. Ensure ‘Show only attributes that have values’ is ticked.

6. Browse in the list attributes and select ‘msExchDelegateListLink’. These are the list of users that the account will automatically map to (populated by those with Full Access to the mailbox).

7. 7. Select Edit, click on the user you would like to no longer auto-map to and select Remove.

8. 8. Press Ok then Apply.

Exchange 2010 - The WS-Management service cannot process the request. The system load quota of 1000 requests per 2 seconds has been exceeded.

When you try to open the Exchange 2010 Management Console, you may receive an error:

The attempt to connect to http://xxxx.domain.yyy/Powershell user ‘Kerberos’ authentication failed: Connecting to remote server failed with the following error message: The WS-Management service cannot process the request. The system load quota of 1000 requests per 2 seconds has been exceeded. Send future requests at a slower rate or raise the quota for this user. The next request from this user will not be approved for at least X milliseconds

The screen looks like this:

Error message

Open an elevated prompt (as administrator) and execute IISRESET .