Teachers cannot access reports and settings
By default, XP gives access to restricted pages (settings, reports, logs, ...) to the teacher role, however when the plugin is used for the whole site this permission is only granted to managers.
To remedy this, a role allowing the permission(s) must be given to the relevant users are the site level.
If XP is used per course, you should double check that your typical teacher roles have been granted the permission.
Which permission to give?
There are more than one permissions to consider, please consult the permissions page to determine which better suit your needs.