HttpError iis config throws exception when default path is added

Question

I have this config which works and redirects the following errors correctly

Answer 1

This is becuase IIS by default (Ive just discovered this with IIS 10) at a server level locks defaultPath.

The error is saying some parent web.config attribute has been locked so you're not allowed to overwrite it.

The way to change this is to

1. Open IIS
2. Select the top level node in the tree (Your server/computer name most likely)
3. Click the 'Configuration Editor' icon in the last row.
4. Enter 'system.webServer/httpErrors' into the section dropdown at the top
5. Right click the defaultPath
6. Go to the 'defaultPath' attribute > sub menu
7. Click Unlock attribute
8. Click Apply Changes in the top right

I'd generally recommend against this though, as you'll have to do this on every server you deploy the site to. (and I'm also not sure how something like Azure Web apps that dont give you this level of access handle it)