Blazor Webassembly PWA

Customer1631

hi, i am trying to setup server for a progressive app PWA.
For downloading webmanifest i need to add type to web.config. but when i do that iis server goes to error 500.

The configuration i'm trying to add is
<mimeMap fileExtension=".webmanifest" mimeType="application/manifest+json" />
in the section
<configuration> => <system.webServer> => <staticContent>

Can you help me?

Thanks