A mishap occurred with web.config to accommodate a subsite existing. I made use of “<location path="." inheritInChildApplications="false">”. Essentially it was a workaround put in place for nested web.config files which was causing a conflict. The result was that error pages were not being handled properly. Error 500 was being passed to the client for every type of error encountered.

Removal of the offending inheritInChildApplications tag from the root web.config restored normal operations of most of the error handling, but for some reason error 503 is a correct response header, but the IIS server is performing the custom actions for error 403.4 which is a redirect to https.

I'm looking to restore defaults for error pages so that the behavior once again is restored. I then can re-add customizations for the error pages.