So to begin, we're using Moodle 2.3.1. Performed an update today to 2.7 and then 3.1, when doing this uploaded the updates to different directories, and I duplicated the database and used a different database and made appropriate changes in the config. Upon completion of this, everything was working fine, with exception to when a student would take a quiz, the quiz doesn't appear to log as an attempt. It seems to go thru as a preview. Went back to the 2.3.1 version, and found that this was also occurring with this version. We've never had this problem before. Anyone have any suggestions on how to solve this issue?
Check the following:
Does the user have another role e.g. admin/teacher? I think that they have to have student role and only student role for it to register now.