After entering my activation key, the hub notified me that I had reached my activation limit, despite me using the key on the same computer as the Hub (+ a separate laptop). I tried deactivating the activation on the local machine and successfully activated it in the hub instead. However, after opening projects in the hub Unity would freeze in the splash screen (not crash, but just not progress any further). I tried re-installing Unity from within the hub, but the issue persisted. I tried opening Unity directly, but it wanted me to activate and I received the error that I had used all my activations once again. Some details: I have a perpetual 5.x license on my account, but this issue happened for a pro subscription I have for my organization, which I have seated to my current account as well. There was no way to stop the hub from using my activation, so I had to reset it through id.unity.com > my seats, which took a while to find, since you can't do this from the organization management panels and the link to deactivate that Unity uses is only for account level keys.