When attempting to load a page or access a feature in Colleague Self-Service, an error message appears that says something along the lines of "Failed to load ___" or "Could not load ___", with "___" being the item that can't be accessed (courses, advisees, etc.)
This type of error can be caused by several different things, but you should always try logging out and then back in to see if that resolves the issue.
Just closing your browser, or even rebooting your computer, will NOT log you out of Colleague Self-Service. You need to click on the "Sign out" button at the top. If you do not have a "Sign out" button, then follow these instructions: Logging Out of Self-Service