site:previewAsAdmin
This component shows detailed error messages on a site in administrator preview mode. We recommend that you add it right before
the closing apex:page tag. Note: The site:previewAsAdmin component contains the apex:messages tag, so if you have that tag elsewhere
on your error pages, you will see the error message twice.
Example
<!-- We recommend adding this component right before your closing apex:page tag. -->
<site:previewAsAdmin/>
