Not authorized to access content that I previously had access to

I received a link from my university for the “Explore the NC Milling Machine Programmer Role” course. I also received a voucher for it. I had previously been able to access the course (as shown in the image):


 However, I now keep getting the message “Not authorized to access this content.” The person in charge at the university couldn’t help me either. Is this due to an error in setting up the eduspace account? My eduspace account is separate from my regular on-premise or cloud account—is that correct? Also, I have two different roles assigned in my eduspace account:

Did something go wrong here?

The voucher is stored in the account, but I get the message “You have already activated this voucher.”

Yesterday, I briefly regained access to the course via a strange workaround:

Logged out -> Logged in via voucher (non-existent account) and then logged in with my existing account. However, this no longer works.

Or is this a browser issue? Do I need to delete any cookies, do I have a broken link, or what is the cause?

Thank you very much for your help!