[SpeedGrader] Better Error Message Needed - An error occurred making a network request when entering a grade

[dmiddletonPTS]

Problem statement:

When the course dates/enrollment dates/section dates aren't valid for today, a teacher will get an error message saying: "An error occurred making a network request" Detail shows: "user not authorize to perform that action Request failed with status code 403"

Proposed solution:

I'm suggesting a more useful troubleshooting error message that infers that this may be because the course is currently closed and/or the enrollment has completed.

User role(s):

admin,instructor