It will depend on how much you failed by. I would rank it as a minor inconvenience, its certainly not akin to a bereavement.
If you were close they might give you a condoned pass i.e within 5%, but you would need to look at your uni rules.
They may be more sympathetic if you passed the non online portion, easily.
The condoned pass is better imo becayse if you just win the appeal they could just ask you to resit again.