If Whit was signed in as you, that would lead to problems. He can check what email address is being used by looking at his Help menu.
This getting signed in only needs to be done after devices have been deauthorized, and also every 28 days. If you’re going to be offline for a couple of weeks it would be worth signing out and in again, so that you have 28 days before you’re asked to do that.
You have two seats, and each seat refers to a single person. Each single person can be signed in on two of their computers, which would allow you to work on your desktop at the office, and on the road with your laptop, for example.
There is a different kind of seats way of working. You could say have 5 seats and 10 people, and so long as 5 or less are signed in, all 10 people could take it in turns to use the seats. That’s how our Network License worked, where a big company would pay us for a year’s worth of perhaps 50 seats, and their 80 architects could have SketchUp installed. The 51st person to try to use SketchUp would see an error message, and hopefully the IT person would have a scheme in place to encourage people not actually using SketchUp to close the program when they are not using it.
That kind of license isn’t around now, other than in some cases where the company is extremely large. It wouldn’t have been offered to small companies in the past either, except for quite a long time ago.
Your QuickBooks might be that kind of license.
If you are sure you are signed out elsewhere, or you have deauthorized all devices, what messages do you see when you try to sign in? If you see any messages, try closing SketchUp and in File Explorer paste in this location:
%AppData%\SketchUp\SketchUp 2022\SketchUp\
In that folder, delete the file named ‘login_session.dat’, and reopen SketchUp.