I want to modernize site pages by following the .NET version of this Microsoft Blog: Modernize your SharePoint Pages I added the nugget package, I use a SharePoint Online Url.
When I get to the code
PageTransformator pageTransformator = new PageTransformator(ctx);
I get the error
Could not find file 'C:\Program Files (x86)\IIS Express\webpartmapping.xml'.
Altough I have the webpartmapping.xml in the project.
Any idea why I get this error?