PC not authorized error when transfering music with iPod Touch

on my iPod Touch 7th Generation, I have a number of songs that are ghosted, and when syncing with iTunes i get an error message saying that that there are 89 songs that weren't copied to it because my PC is not authorized....I have authorized it 3 times today-first when downloading some CDs, and again when I got the message that says to authorize the computer. The 2nd and 3rd time both come back with "you are already authorized"....what can I do?

[Re-Titled by Moderator]