You get a launch error when there is missing or incorrect data in the launch that is sent from the Learning Management System / Platform.
Detail: This error can mean one of several things happenned. You might have simply stopped using this page for a long while and your session expired. Alternatively, something about your Internet connection changed or you switched to a different browser. Perhaps your computer went to sleep and woke back up with a different network address. Or perhaps you tried to bookmark a direct link into this tool - which does not work.
To solve this go back to the learning system where you originally launched the tool and relaunch the tool.
One of the first things to check is to make sure that both the tool and LMS / platform are officially certified at https://www.imsglobal.org/cc/statuschart.cfm