i have some local files that are syncing fine, other will not sync. the playlist says it is downloaded on my phone with 0 tracks. the files play fine on my computer with spotify and some have even synced with my phone in the past, but will not now. i have tried syncing via wifi and usb. all of the files are the same file type and in the same folder on my computer. i have plenty of space for them to sync on my phone. i have tried deleting cache and data on my phone and reinstalling as well as moving the local files to a different location on my computer. some from one playlist always sink while others will not. all by a certain artist will not sync. i am so confused... please help!