Whenever I try to download something from Itunes to my laptop, it says "stopped (err= -50)", but my internet is working and I have enough free space on my startup disk

I keep trying to download stuff to my Itunes Library but it always says "Stopped (err= -50)". This hasn't always been happening, it is a recent problem. It does give you a reason why the error occurred, like for err= -50 it says, "Please check that the connection to the network is active and try again." I check, and it works fine, it always has been working perfectly, so it can't be the reason why it's not working. It also sometimes tells me that there is not enough free space on my startup disk, but then I made a lot more free space by deleting files, and it STILL doesn't work.