@KaidinFields 
I'm sorry you're experiencing that, I'm sure it's frustrating. 

You may want to begin by checking the due date and time - ensuring you are not past when the assignment will be accepted. 
If it's not past due, check your browser and computer requirements for Instructure products to ensure they are compatible. 
If all of that checks out, reach out to your Instructor as soon as possible to let them know you are experiencing a problem and see if they can help you with your submission.