Hello,
I am experiencing an issue with your MMM-WebUntis module. Despite following the setup instructions and providing the correct credentials, I am unable to log in. After testing, I believe the issue may be related to the presence of an umlaut (e.g., ö) and/or a whitespace in the school name.

My Setup:
MagicMirror Version: v2.29.0
MMM-WebUntis Module Version: Latest from repository
School Name: Contains an umlaut (ö) and a space
Login Method: My school uses iserv (iserv.de) for authentication. I do not have direct login credentials for the WebUntis portal but instead rely on the QR code provided by the school, which works in the official WebUntis app.

Configuration:

Here is an example of my configuration (with pseudodata replacing sensitive values):

{
  module: "MMM-Webuntis",
  position: "top_right",
  header: "WebUntis Schedule",
  config: {
    students: [
      {
        title: "Student1",
        qrcode: "untis://setschool?url=kadmos.webuntis.com&school=schulname with ö and space&user=username&key=ABC12345&schoolNumber=1234567",
        useClassTimetable: true
      }
    ],
    days: 10,
    mode: "verbose"
  }
}

Error Messages:

Here are the errors I encountered:

When using the QR code:

[LOG]   ERROR for Student1: Error: Request failed with status code 400

Debugging with the check.js script

Error: getaddrinfo ENOTFOUND undefined

When manually entering the school name, username, and password instead of using qrcode:

Error: Failed to login. {"jsonrpc":"2.0","id":"Awesome","error":{"message":"bad credentials","code":-8504}}

Observations:

The QR code provided by webuntis contains the following (copied directly from the QR code content):
You see, the miscoding of the ö.

untis://setschool?url=example.webuntis.com&school=school name with � and space&user=username&key=ABC12345&schoolNumber=1234567

Notably:
The umlaut (ö) in the school name seems to cause issues.
There is also a whitespace in the school name.

Even when encoding the URL (e.g., using %C3%B6 for ö and %20 for the whitespace), I still encounter errors. I tried various configurations, including:

"school%20name%20with%20%C3%B6%20and%20space"
"schoolname with ö and space"
"schoolname+with+oe+and+space"
 ...

The QR code works perfectly in the WebUntis app, so I believe the credentials and format are correct. But my school uses iserv for authentication, meaning I do not have a standard WebUntis username and password.