When the teacher visited Moodle at home and tried to grade the assignment of students, it prompts a blank page with an error message "Undefined" at the center (as image shown). She cannot assign any grade at all.
However, if she connected her office PC by using remote desktop, she can normally grade the assignment with her office PC inside campus. It seems that it only works normally inside intranet but not inside internet.
What is the cause of the problem? Please advise how to resolve this problem. Thank you very much.