Hello TheMaartian and welcome to the forum.
TheMaartian wrote:I tried resetting via the Custom Shop, but no help.
By this, do you mean that you did Gear>Restore My Gear in the Custom Shop app?
If so, this should have sorted any issues out, as long as you have used the AT4MAX serial number in the Authorisation Manager.
As this is a user-to-user forum and not direct to IKM support, in case no one else chimes in here with advice or a solution, you should raise a ticket with IK official support here
https://www.ikmultimedia.com/contact-support/sw/They endeavour to reply within 2 working days, but obviously considering the current situation things may take longer than usual.
Be aware however, that the Brian May collection along with a couple of others are not included in the AT4MAX package. If you can see collections from Ampeg, Fender, Orange etc then your MAX package is working correctly.