Cannot download music to Apple Watch via iPhone

I want to add and download certain playlists to my watch but I am unable to do so.

I've been able to do this in the past, but it's been a while since I have. I have also since recreated my iTunes Library. I am an Apple Music subscriber, but it's songs I personally own and have downloaded to my computer and iPhone that I want on my watch.

I can select the playlist I want and I can see the tracks within that playlist, but they are not selectable / the text is dimmed. All the tracks in any selected playlist appear this way. I've tried restarting, reseting, removing and reconnecting my iCloud account from iTunes, updating iCloud music over and over, but it's not making a difference.

When I select the "+" at the top right of the screen it appears for a moment as if I successfully added the playlist to my watch, it says "Your music will download soon," then it doesn't and a message appears that says "Could Not Connect to Apple Watch." The watch and iPhone are both on wifi, plugged in, and sitting on the desk, side-by-side.

Does anyone know how to resolve this?

Thanks