Previously, I was able to play music on iTunes without a Wi-Fi connection. Now, I get an error message and my music will not play. WHY?
How can I play my music through iTunes without a Wi-Fi connection?
I traced the problem down to a TLS handshake and a total of 63 packets between the host and 18.104.22.168, which is init.iTunes.apple.com - that is executed when the current version of iTunes is started. Once this handshake completes, all is fine. But you must tunnel traffic to this host on startup, otherwise you get the error with each and every song change.
You can play music without wifi if you have an internet connection when you start iTunes. So, connect your laptop to the internet and do not turn it off/close iTunes, just put it to sleep. Then, the error will not appear. Not a fix, but it works.
Are the songs you are trying to play on iCloud, or actually downloaded to your computer's hard drive? Sometimes it can appear that they are but the song is actually not stored locally.
And if it is stored on your hard drive, sometimes something moves the file and iTunes loses track of where it is located. You can right click on the name and use Get Info (or the equivalent for your version of iTunes) to see the file path.
There was also an issue with one version of iTunes where it deleted non-iTunes music for some users until they fixed that.