This might be due to the tornadoes in Oklahoma or could be something your local ISP is doing . . .
When I checked on this last year (Fall 2012), Comcast and a few other ISPs were doing a bit of throttling as a way to "manage" their web traffic. You can do a web search on it and probably get some information on whether they continue to do it . . .
This happened last year for a few folks when NOTION 4 was released, and there was a big discussion and investigation about it, with the result that it was due in part to hurricane Sandy and the affects it had on web traffic in the US, but it also was due to the ISPs of some users . . .
It was
not due to the servers that Notion Music uses . . .
The best advice is to keep trying, and you might want to ask your local ISP about the problem, really . . .
Really!