My guess is that you are on a Windows machine. If you are actually on a Mac, please let us know- that has a different fix.
It is a permissions issue.
Here’s what you are going to want to do:
Disconnect your Connect program-
Click in the bottom right of your screen on the up arrow, right click on the flask icon and select quit:
Open this folder on your computer (its hidden, you’ll have to unhide folders)
You should have an unzipped folder there called Virtual ChemLabWin (or Virtual __ Lab- whatever lab you are trying to install)
Please drag that folder to this location:
Now refresh your browser (ctrl+r) and login again, connect again and hopefully the lab will say open this time!