HTTP error 500
Symptom
When connecting to the DataMiner Dashboards legacy app, you get the following HTTP error:
HTTP Error 500.19 - Internal Server Error. The requested page cannot be accessed because the related configuration data for the page is invalid.
In the Detailed Error Information section, you find the following Config Error:
The configuration section 'system.web.extensions' cannot be read because it is missing a section declaration.
Cause
The problem can have two causes:
The application pool that is being used for the application (e.g. DataMiner Dashboards) is not configured to use Microsoft .NET 4.0 yet, OR
there is a problem with IIS where the configuration of .NET 2.0 is read even for application pools using .NET 4.0.
Resolution
To resolve the problem, open IIS and check whether the DataMiner Dashboards application is running in an application pool that is configured to use Microsoft .NET 4.0. If not, proceed as follows to change the Application Pool (AppPool) settings of the DataMiner Dashboards application:
In the tree structure on the left, select the application directory.
In the Actions section, click Basic Settings... The application pool will probably be set to “DefaultAppPool”.
Click Select... and change Application pool to “ASP.NET v4.0” (or another .NET 4.0 application pool).
Click OK.
Reconnect to DataMiner Dashboards.