When the "Authentication problem. Please contact support." message is received, it often means 3rd party cookies are being blocked.
If you are unsure of how to check this setting, here are some resources that can help:
Why is UDOIT considered 3rd party?
UDOIT is considered a 3rd party tool because it's a separate web application that is pulled into the LMS through an i-frame. The 3rd party cookie is needed to remember who the user is between page refreshes, which is why the error has an "authentication problem" when the cookie is blocked.
If you have checked to see if 3rd party cookies are being blocked and are still receiving this message, please submit a ticket through our support portal and we will get back to you shortly.