ApplicationSettings vs AppSettings (edit)
https://stackoverflow.com/questions/2906406/applicationsettings-and-web-config
HTTP Error 500.19 - Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid.
The configuration section 'applicationSettings' cannot be read because it is missing a section declaration
https://docs.microsoft.com/en-us/troubleshoot/iis/http-error-500-19-webpage
