Kindly refer to this thread: https://community.gopro.com/t5/Cameras/Why-do-I-need-3-Gb-of-free-space-to-upload-media-to-the-cloud...
You can also check this article.
Have you tried following suggestions above?
Make sure you have stable internet connection and at least free 3GB space on your SD card.
Let us know how it goes.