Cannot load music on Apple Watch (series 3)

Hi all:

I have tried all the common suggestions for this problem to no avail (restarting both devices, making sure Bluetooth and WiFi are on, making sure the watch AND phone are charging, updating the watch to the new iOS, etc.).

I'm at a loss. How can it be this difficult to transfer music (on my phone and the cloud)? Everything else is working seamlessly, but this is really frustrating. Podcasts are loading, but I cannot get a single song/album to load onto the watch. I tried leaving it loading overnight, and it was still spinning in the morning.

FYI: Using an iPhone 8 and watch is Series 3 (no cellular). Both have the latest iOS.

Please help!