How to create custom error pages

Resolution

If it is necessary to use .php., .asp, etc applications on the domain.

First of all make sure that this extension is allowed in IIS and for the domain.

In Plesk Control Panel create a virtual directory for custom error document files: Domains, domain.name, Web Directories, AddNewVirtualDirectory (it will be created on the server in %plesk_vhosts%domain.namehttpdocs)

Create a new file (script that will be run on this error):

Domains, File Manager, httpdocs, Created Virtual Directory, Add new File

Choose created file to be processed for the needed error:

Domains, domain.name, Web Directories, Error Documents, needed error , Location.
It needs to specify it in the following manner:

Type: URl

Location: /Created_Virtual_Directory/file.name

Note: Do not create custom files in %plesk_vhosts%domain.nameerror_docs directiry, it will not be processed, because %plesk_vhosts%domain.namehttpdocs used as home directory for custom files.