I'm using the new integrated Parsoid (PHP Version). On one server it works without problems, but on another server i get the following error:

Error contacting the Parsoid/RESTBase server (HTTP 404)

The configuration on both servers should be identical.

Parsoid config:

wfLoadExtension('Parsoid', 'vendor/wikimedia/parsoid/extension.json');
$wgVirtualRestConfig['modules']['parsoid']['url'] = 'http://localhost' . $wgScriptPath . '/rest.php';
$wgVirtualRestConfig['modules']['parsoid']['forwardCookies'] = true;

When i enable the debug log there is one difference in the log when i'm opening the Visual Editor that i can't explain.
Working server:

Start request GET /w/rest.php/my.domain.net/v3/page/html/Main_Page/40?redirect=false&stash=true

(i replaced the actual domain name from the log with my.domain.net)

Not working server:

Start request GET /w/rest.php?redirect=false&stash=true

Do you have any idea why it doesn't work on one of the servers?

Information about the server where it works:
MediaWiki Version: 1.35.1
PHP Version: 7.3.26
Web-Server: IIS 10 (Windows Server 2016)

The server where it doesn't work:
MediaWiki Version: 1.35.1
PHP Version: 7.3.26
Web-Server: IIS 8.5 (Windows Server 2012 R2)