If you have used LockDown Browser at another institution or downloaded LockDown Browser using the wrong web link may bring a different school's login page and that might prevent you from accessing your test.
Each institution (and product) has a unique download link for LockDown Browser.
FIX: First uninstall the copy of LockDown Browser you have on our computer, and then install the version from the institution you intend to take a test. Here at NWU you can access the NWU LockDown browser from the Canvas site most likely alongside the quiz or exam you will be taking or using this link: Download LockDown Browser (respondus.com).