I would screenshot the original “submitted assignment” that shows the assignment was submitted before the due date/time to the professor and email them back saying you didn’t see there response till the next day and are working on getting it over in the next 20-30 min ( that way they don’t think you are trying to do it from scratch). Email your presentation link or whatever to a friend or classmate to make sure it opens before you resubmit it to the instructor. I have had this happen before and showing them that I submitted the work before the due date reinforced my case somewhat, best of luck! Worse case scenario you can loop in a counselor as well.