Q: iTunes Match authorization

I’ve had an iTunes Match subscription for a few years now (since before Apple music), but recently I haven’t been able to access my library from the cloud on the family iMac. When I click to play or download any song that I have stored in the cloud, this is the message I get:

This computer is already associated with an Apple ID.

You can use iTunes Match on this computer with just one Apple ID every 90 days. This computer can be used with a different Apple ID in 40 days.

I have no other computers authorized to use my Apple ID, and have checked this multiple times, even deactivating all activated computers in my account settings then reactivating this iMac for use with my Apple ID. I only have one Apple ID, and no one else in my family uses iTunes Match.

Why am I not able to use my Match Library anymore? Any help would be much appreciated!

Thanks in advance,

— Joel