Getting random bytes after installing 25.0.4

I installed 25.0.4 on a fresh webspace with PHP 7.4. The installer wizard was showing up, everything looks fine, i entered an admin user and my database credentials. After that i get this following response:

Any ideas?

How did you install Nextcloud? Unzip the files and upload? You run the installer wizard via the browser and there everything looks normal? Logfiles?