FWIW, I work for an ISP in Australia. On occasions, we have found that long distance file transfers fail due to server time-outs. Due to Australia's remoteness from many major data servers, particularly in Europe and the USA, latency can be a problem. It's not actually the distance that the data travels but the number of routers that it must traverse, each adding a little queuing and packet/address analysis delay.
In addition to this normal long-distance latency, using a wireless (mobile/cellphone) data connection at either end of the connection will add enough latency to make data transfers unreliable. Often the data eventually reaches its destination but the handshake packets do not reach the server and/or client before a time-out occurs.
I can't say what the problem was in this case. Internet browsers can be flakey at the best of times. However, it can be beneficial for operators of web servers to increase the timeout limits on servers where long distance uploads and downloads are expected.