<system.webServer>
        <staticContent>
            <clear/>
            <mimeMap fileExtension = ".*" mimeType="text/json" />
        </staticContent>
        <handlers>
            <clear />
            <add name="StaticFile" path="*" verb="*" type="" modules="StaticFileModule,DefaultDocumentModule,DirectoryListingModule" scriptProcessor="" resourceType="Either" requireAccess="Read" allowPathInfo="false" preCondition="" responseBufferLimit="4194304" />
        </handlers>
    </system.webServer>

/.well-known/acme-challenge/emptyTextFile

<system.webServer>
    <httpProtocol>
      <customHeaders>
        <add name="Strict-Transport-Security" value="max-age=16070400; includeSubDomains" />
        <add name="Content-Security-Policy" value="upgrade-insecure-requests;" />
      </customHeaders>
</httpProtocol>