Plesk - Custom Error Page
Process of edit custom error page.
Step 1 - Log in to your Plesk control panel.
Step 2 - Go to the “Websites & Domains” tab and choose which domain you’d like to secure.
Step 3 - Select Virtual Directories.
Step 4 - Click on Error Documents.
Step 5 - Click on any error page which you want to edit.
Step 6 - Select Type (File, URL, Default).
Step 7 - Provide the file name and url then click on OK.