Canstock support answer:
Posted: October 9, 2015 9:16AM (3 days ago)
"Hi Ana,
we have looked into this matter and found that there was indeed a bug on our site, causing this upload problem. The problem is being fixed at this very moment and your images should appear in your "unfinished" folder shortly.
I apologize for all the inconvenience this must have caused you.
Regards,
Sorina
Can Stock Photo Support"
today i try again and the bug still there :-(