I've been trying to track down this issue for a bit now for a client, but because of it not showing up all the time, it's been tough. Essentially when an image is being uploaded, it's says "Uploading...", but gets stuck there & doesn't proceed with finishing the upload process.
It's never done this for me, but for my client, it's both been successful & failed in IE/Firefox/Chrome/Safari on different computers on both PC/MC platforms on multiple different internet connections (at home & office).
I tried simulating heavier backend usage (was logged-in in multiple browsers & attempted to do multiple backend functions while an image upload was taking place & it uploaded fine). I also looked at the server usage logs & at all of the times they were having issues, there were no traffic spikes. They also have decently high speed internet. So I think it's safe to say we can rule out these things.
Not sure what else to check. Any ideas?
They're on Magento 18.104.22.168