When you disconnect in a running class, at times it may take a minute or two for the servers to actually log you off from the class. So if you try to enter the class again within such time, you are shown the message that this user already exists. To resolve this error, try one of the following steps:

1. Close the class window and launch your class again. If does not work, try launching the class in a different browser.

2. Copy and paste the class link in a new browser window.