Good Day togehter!

I'm having a OSTicket on a Webserver hosted by Swiss Hoster "Hostpoint".
I tried to implement Microsoft 365 Authentication, but it won't work.

What make i wrong? Where is the bug?

First of all i have the following OSTicket Informations:

I installed the plugin and configured it properly (followed the docs from osticket)

If i then test it with a Microsoft 365 account from the tenant (example@domain.com) it won't work. It's showing me the following error:


My .htaccess looks like the following:
<IfModule mod_rewrite.c>
RewriteEngine On

# Exclude existing files and directories from rewrite
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} (.*/api)

# Rewrite URLs that match the /api pattern
RewriteRule ^api/(.*)$ http.php/$1 [R,L]

</IfModule>

Based on a talk with KI / AI i got the follow solution for checking about url rewriting:

2. Überprüfung durch ein kleines Skript
Du kannst ein kleines PHP-Skript in deinem Webserver-Dokumentenstamm erstellen, das speziell für das Testen von URL-Rewriting formuliert ist. Lade eine Datei mit folgendem Inhalt hoch:

Erstelle eine Datei test_rewrite.php:
<?php
if (isset($_GET['rewritetest'])) {
    echo "URL rewriting is enabled.";
} else {
    echo "URL rewriting is not enabled.";
}
?>


Erstelle eine URL-Rewriting-Regel in deiner .htaccess-Datei:
RewriteEngine On
RewriteRule ^test-rewrite$ test_rewrite.php?rewritetest=1 [L]

Versuche dann, im Browser die URL http://yourdomain.com/test-rewrite aufzurufen. Wenn URL-Rewriting korrekt konfiguriert ist, sollte die Nachricht "URL rewriting is enabled." angezeigt werden.

I'm with my knowledge at the end.
Can anyone assist me solving my problem?

Greetings,
calgia