Unable to validate server "Issues Found": ArcGIS Server service URL 'https://maps.example.com/webadaptorname' cannot be validated against 'https://maps.example.com/rest/info'

Description

When attempting to validate an ArcGIS server, the server generates an "Issues found" message along with a message similar to the following:

ArcGIS Server service URL 'https://maps.example.com/webadaptor' cannot be validated against 'https://maps.example.com/rest/info'. If the service URL is a proxy URL verify it is accessibly to clients. Error:java.lang.Exception: Server returned HTTP status code 503.

Cause

The web adaptor may have missing or corrupt files, which prevents communication between the two URLs referenced in the error message. A repair must be run on the web adaptor.

Solution or Workaround

Repair the web adaptor of the ArcGIS Server machine that generates the 'Issues found' message:

1. Navigate to Control Panel > Programs & Features.
2. Right-click the web adaptor that requires the repair and select Change.
3. Click Repair and click Next.

Once the repair is complete, attempt to validate the server again. This should resolve the behavior. If it is not resolved, the next step is to uninstall and reinstall the web adaptor, following the guidelines described in: Install ArcGIS Web Adaptor