Make sure your profile country matches your country you are in and you are using the right log in details.
It may be helpful to know if you have premium or unlimited. Also, are you traveling across various countries?
A clean installation may also help your problem if the advice above doesn't work (408 should never happen with unlimited or premium). Your playlists will be saved in this process, but you may need to redownload of line playlists synched to your device.
~Soli Deo Gloria~ * If you see a single asterisk like before this sentence, it most likely denotes sarcasm.