Whenever you see anything like that, it’s often a problem with the cookies or cache in the browser. Our authentication processes rely on cookies and cache, and accessing a lot of resources can cause these to just sort of get messed up. There are some directions here for clearing your cookies and cache in different browsers: https://its.uiowa.edu/support/article/719
If you’d prefer not to clear ALL of your cookies and cache, you can still clear specific ones if you’re using chrome by going to these two links and hitting the “remove all shown” button
chrome://settings/siteData?searchSubpage=csun
chrome://settings/siteData?searchSubpage=exlibris
That will reset all the files involved with CSUN and Ex Libris sites and tools while keeping everything else intact.
