iTunes Match restarts on step 3 when trying to upload files When I add new songs to iTunes and Match needs to upload them (on step 3), it restarts back to step 1. So it gets stuck in an infinite loop by reaching step 3, trying to upload but failing, then resetting back to step 1.

How can I fix this? I already tried the simple things like restarting my computer and turning off and on iTunes Match, and deleting and re-adding the songs back to iTunes.
I encountered this problem, and it turned out that it was due to my ISP's traffic shaping. Uploading my music was saturating my upload bandwidth, and after about 5 minutes of that, my ISP would cut my connection to Apple's servers for a few minutes, causing step 3 to time out and the whole thing to restart.

I fixed the problem by setting up bandwidth throttling on my router while I was uploading my library. Setting it to about 80% of my maximum bandwidth worked well.