This happens all the time for me. I can only download just a few tiles, then that IP is blocked. I can't even download the tiles covering the area where I live, just a few square kilometers: after a little while it fails, and I have to switch over to VE or any of the others, or move to another IP. I'm not sure how long it stays blocked, a day maybe (I usually don't try it anymore that day so I'm not certain).