ITunes Match won't upload non-matched songs on my home network

Question

As it says in the subject, iTunes Match won't upload non-matched songs on my home network. For a while I thought the problem was with iTunes Match itself. And maybe it still is somehow. But I recently discovered the problem only occurs on my own home network. Any time I add a song to iTunes that isn't in the iTunes store, it should upload it. But instead it just loops in failed attempts to upload, always stopping and starting over at step 1. Occasionally I'll get error messages like -9810, but more often it'll just continue to loop for hours on end. I recently took my MBP to a coffee shop and used their wifi and tried it there, and the songs uploaded without any problem at all. I never used to have this issue over the entire year I was using iTunes Match. My only guess as to what might have caused the issue is when we downgraded the speed of our internet. I can't recall for certain whether that was the exact time my issues began, but it's the only possible change I can think of. I've tried rebooting the router, turning iTunes Match and Genius off and on, rebooting the computer, creating a new iTunes Library, all not solving my problem. Any other ideas?

Answer 1

There's a longer thread discussing this problem over here: https://discussions.apple.com/thread/4160355?start=120&tstart=0
What I posted there is that if I enable QOS on my router and limit my upload bandwidth (I used a cap of 1024 kilobits/second) then iTunes Match stops looping and will successfully upload songs and complete match.
There aren't any blocked ports, it's really just iTunes being a pig and oversaturating the internet connection to a point of failure.
Super frustrating, it's been a bug for months. I wish I had a better solution.