Codeigniter 4 in IIS Webserver

Hello,
In my organization we want to use our Windows Server 2019 IIS to develop and produce real Codeigniter projects.
We have seen the server requirements in the official Codeigniter documentation:

PHP version 8.1 or later and these extensions enabled:
- international
- character string
-json

All the requirements work because we have checked them using the phpinfo() function.
Unfortunately, when we navigate to the /public folder to display the project in the browser, this message appears:
Oh! It seems we've run into a problem. Please try again later...

This is somewhat annoying for us and we did not find the problem. We have searched and read a lot about this error but apparently it is an error with the extensions, which are already activated, or a generic error.

I was wondering if anyone could help/advise me to resolve the issue.

Thanks in advance.