Simplify error handling in code

[GermanS]

Dear F3kilo

This pull request aims to simplify the error handling in code by refining the way we return error messages.

• Replaced the use of String::from("No message provided").into() with a more concise return statement: Err("No message provided".into()).

This change improves code readability and maintainability without altering the functionality.

Please review the changes. Thank you!