I uploaded a file earlier, and I must have flipped some frames as I was creating the head, and it got denied for frames being wrong. I fixed the issue and tried to reupload it and this is all that happens, created a new file, tried on a different device to no avail.
Ensure the file dimensions match that of the template, that's the first thing that comes to mind for me.
Heads should be 32x560, if I recall correctly.
It didn't seem the file wasn't an issue, rather a problem with the website. It has since resolved. Thanks to the staff member I messaged regarding the issue aswell.