With ProQuest e-books, they will time out after 30 minutes of inactivity. This happens when you have an e-book open and ignore it or sometimes ProQuest will detect a previous session where you had an e-book opened in a tab in your browser and then when you try to return to the e-book, it gives you the message that your session has expired.  Usually, refreshing the page will bring it back.

If that doesn't work, try the following:

• Click on the Sign Out button in the upper right corner of the e-book and then use the URL you used to access the e-book to sign back in.