Error:
"Server Error in '/' Application. Exception of type 'System.OutOfMemoryException' was thrown" results in being unable to view the lansweeper dashboard via http.

Description:
After upgrading to version 4.2.0.56 I was unable to view lansweeper via the local web browser (http://127.0.0.1:8080/)

Solution:

I checked to make sure the Lansweeper service, SQL Server service & IIS Express service had restarted after the upgrade. Even though they had, multiple attempts to view the webpage failed.

I restarted each of those services in the following order:
SQL Server
Lansweeper
IIS Express

Trying the browser again I was now able to view the dashboard. :)