Open regedit on the server
Go to HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
Create a new DWORD value “Reread Logon Quotas Interval” (without the quotes) and give it a decimal value of 1200 (20 minutes in seconds)
Still under the key ParametersSystem, create a new DWORD value “Mailbox Cache Age Limit” and give it a decimal value of 20
Restart the Exchange IS
