Some of my students had no issues submitting files for an assignment, while others are unable to even view the submission options on the same assignment page. They've tried clearing cache, using different browsers, and refreshing the page. I also tried turning off the TurnitIn extension. No dice.
In addition, when I try to use the grade book to Submit for Student, the file uploads successfully, but when I click "submit," I get an "Error sending submission" message.
What gives?