MIXAMO isn't receiving my uploads

I have been trying to upload my FBX file which I download from sketchfab, I tried it from different systems as well but Mixamo says that they cant recieve my upload, I have been at it for many hours now , I checked the mesh and followed some YT tutorials as well but It didnt help. I am attaching the screenshot of the notification that it shows and also the file, Your help would be very much appreciated, Thank you.