When a student uses multiple browsers or two devices at once, it can prevent the completion state of an activity from appropriately setting, which will prevent the student from proceeding in the course.

If the course is Prescriptive or Sequential, this will prevent student progression. Any activity can be completed by the Teacher within the Gradebook. To resolve this issue, the teacher can force-complete the activity by following these steps.
To Mark a Non-Gradable Activity Complete:
- Select the Gradebook tool from the desired Course Card on the Home page.
- From the Gradebook, select Display options from the Header Menu.
- Scroll down to view Other view options.
- Select Show Non-Gradable Activities.
- Find the activity in the Gradebook. Select the empty field where the score normally displays for the user.
- The student name and activity displays in a popup window. Select Mark Complete.
- The Gradebook displays a green check to show activity is complete.
These steps will mark the activity complete and allow student progression within the course.
For more information, review this video on Marking Non-Gradable Activities Complete.