When attempting to login to the hosted instance, the below error is received indicating that the user is already logged in.
There are two things that can cause this-
1. A user can only be logged into a single instance at any given time. The user may currently be logged into a different instance.
2. The user did not correctly log out of the instance they are attempting to access, and therefore is still logged in.
Take the following steps to resolve each of the two causes:
1. Ensure that the user is not logged into any other instances.
2. When closing out the web-browser it is necessary to log the user out, as opposed to just closing the web-browser. Failure to log out prior to closing the browser will result in this error.