Beware, NeoLoad does not detect all errors automatically. Even if HTTP error codes are detected by NeoLoad as a cause of a failed validation, functional errors (such as the incorrect playback of a business transaction) can escape detection. This is because applications often return pages in error that contain valid HTTP codes. Therefore, it is important to make sure that the content or HTML rendering does in fact correspond to the expected result. For example, an incorrectly played-back login often produces an HTML page stating that "the login or password is incorrect".

Validate first your Virtual User with the Check VU dialog (see Checking a Virtual User)

Learn more about the whole design process in the documentation.