Subscription won't activate

Hi. Bought a 2021 Pro subscription after the trial ended, used the correct email/login, etc, and Pro still won’t activate. Anyone else have this problem?

Try logging out and than restart SketchUp. If one forgets to tick the checkbox, it’s not automatically assigned.
You can check if you go to myaccount.trimble.com and check the Member section, be sure that the email address has ‘Product Access’
Modify with the three dots on the end.

Is the “product seat” automatically assigned to the computer you buy it from? Or is it possible Sketchup assigned the seat to the wrong computer?

Subscriptions are assigned to email addresses, not particular computers. Normally it defaults to being assigned to the email address of the person placing the order, but it is possible for that option to be unchecked. In your case the subscription hasn’t been assigned, but you are the admin for the account. Going to the Members section Mike mentioned should let you then assign the seat to the email that needs it.