Product upload fails

I've been encountering this issue where the upload completely stops when it nears the end these past several videos I've created. It's a very hit or miss situation where sometimes the upload runs smoothly, but sometimes it wont upload for weeks. It's really annoying when I wait for hours trying to upload a file size that's over a gig and the upload stops at the last few mb.... I thought it was my computer so I tried uploading using another computer, but the same problem occurs... I don't encounter this problem when I upload to gumroad or Artstation to sell my product. The problem only seems to happen on cubebrush. The upload wheel keeps spinning, but the upload seem completely stopped...I also tried clearing cache and cookie, but still no good... Anyone have answer to this?

here's a screenshot showing exactly what's happening... So looks like these files uploaded completely, however as you can see on the left, there's the spinning 4 dot wheel that never ends and it has been stuck like this four hours. I cannot save or upload the files. I have to retry the upload again....