This error can occur for "auto-launch" environments (D2L, Schoology) when any of the following are true:

1) Your Respondus server profile is hidden. You'll want to ensure that your server profile is set to "No" for the setting "Hide this server from LDB."

2) If you have multiple LockDown Browser "apps" installed on your Mac. You can only have one for auto-launch to work.  All extra LockDown Browser apps need to be moved to the trash, and then the trash should be emptied.

3) It's possible you have installed LockDown Browser using an installation package that contains the wrong institution ID. As a troubleshooting step, perform a reinstall of LockDown Browser, downloading the latest install package via your unique LockDown Browser download URL. Once the reinstall is performed, try taking the exam again.

4) For Schoology, if you have specified a URL of "app.schoology.com" for your Respondus server profile, you need to ensure that students are logging on using that URL. If your Respondus server profile has the "vanity" URL specified (example:  respondus.schoology.com) then students should log in using that URL.

5) For Windows users, it's possible that you might have multiple LockDown Browser shortcuts present, each with different institution ID's.  This is rare, but can occur when students need to use LockDown Browser to logon to more than one institution.  In such a scenario, you need to ensure that the actual installation of LockDown Browser on your computer directs you to the institution that is using auto-launch.