Logging into the Messaging Gateway (SMG) control center results in an immediate "Application Error...".
Attempting to view the "Status" page results in the error "Application Error...".
"The application encountered an error. If you are the administrator, please check the log files for details.
Click here to return to the previous page"
The application error is being returned by the Status Page (also referred to as the Dashboard). There are multiple issues that can cause this.
This situation has multiple solutions. One workaround is to manually go to another page in the Control Center:
(NOTE: This URL is for version 10.6.x of SMG and may change in future releases)
For further troubleshooting the issue, look in the brightmaillog.log or open a support case.