Q: Cannot transfer content to iPod

Hey,

I've never had a problem with using iTunes or any of my devices in the past, but in the las week or so, I have not been able to transfer any media to either my iPod or my iPhone.  I find this very strange, as I haven't changed any settings on either device, nor have I changed anything on my mac.  I haven't been using the iCloud music library, and all of the "Manage music manually" boxes are still ticked the same way they always have been.  The only thing that has changed in the last month or so, is I've updated everything to the latest software version (including upgrading to El Capitan), and I've subscribed to Apple Music.  Anyone else having a similar issue, or is this just a fluke?  Also, how would I go about fixing this?  This is driving me nuts!

Thanks,

- Jeff