I have to say this is the most frustrating user experience I have ever had. This isn't the first time I had to do this. I was invited to the studio last month. Then come to find out my account no longer exists even though I show in the users list of that studio. They then invite me back and neither of my accounts (personal, business) work. I click the accept invite and just go to the main page. It never accepts. I have tried on both accounts.
This also happened the first time I tried to join.