Exchange 2007 OWA "Insufficient Access Rights"

Occassionally, after transferring a mailbox from Exchange 2003 to Exchange 2007 OWA will not function for that mailbox. The user will receive a message "The user has insufficient access rights." To resolve this perform the following:

1. Launch Active Directory Users and Computers
2. From the View menu, select Advanced.
3. Locate the user in AD, right click, properties.
4. Navigate to the security tab.
4. Click "Advanced"
5. Click "Allow inheritable permissions from the parent to propagate to this object and all child objects.
6. Click Apply
7. Click OK and OK again.