Student Technology Services does not provide direct, student-facing training on using Packback. In lieu of providing these services in-house, we curate 3rd party resources that can help support students.
The 400 error in the LMS is a common issue. It is often related to the browser not accepting cookies, but it could also be related to something else.
To learn more about troubleshooting, view this Why am I receiving this error: 400 “Enable Cookies”?