I have just had the same issue. It connected to my host and got into the right folder and then just sat and I waited and waited and nothing more happened.
When I paused my Avast it uploaded immediately. So looks like a conflict with virus protection programs is a common issue.
It would be good if the program would actually tell you it can't upload and suggest turning off virus protection. As it is it tells you nothing and you sit there waiting like a child waiting for Christmas.
I know you believe you understand what you think I said...but I am not sure you realize that what you heard is not exactly what I meant.