About once a day we get the following error in our IMail web-client:

Server Application Unavailable

The web application you are attempting to access on this web server is currently unavailable.  Please hit the "Refresh" button in your web browser to retry your request.

Administrator Note: An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur.

Restarting IIS fixes the issue. No error message detailing the cause of this failure is found in the event log of the web server...

Anyone who knows a fix?

Regards,

Nika.