If you're using Windows 10 and plugged modem as your main connection, experiencing "Waiting for Connection" when you want to download songs at Spotify Desktop app (downloaded from website),
You are at the right place and one step closer to fix this problem!
It's disappointing when Spotify Desktop App can't detect connection from plugged old modem. I have tried trial and error to solve this problem, and come to one conclusion, let me explain the steps!
1. You need to provide connection besides your plugged modem, I used wi-fi hotspot from my Android smartphone (of course, it's connected with my spotify desktop app)
2. Make sure your modem is connected first! (check the status of your connection from your taskbar)
3. Check your Spotify Desktop app, check which playlist that encountering the "Waiting for Connection" issue, after that, turn off the downloaded playlist, close your Spotify Desktop app.
4. Now connect your pc/laptop to your Android Hotspot! (check from taskbar and make sure you are using wifi, not the modem)
5. Open your Spotify desktop app again, and turn on the download option from your preferred playlist. Your playlist should display "Downloading" and you can see the progress of how much songs need to be downloaded depends on your playlist, of course.
If you already downloaded songs, turning off the download option won't delete your songs. Don't worry.
6. Now is the critical moment! After you already sure that your songs is downloading steadily, manually disconnect your Android hotspot from the taskbar, so the taskbar of your pc/laptop should see the modem icon (usually it looks like signal bar)
WAIT FOR A FEW MOMENTS, YOUR SONGS WILL CONTINUE TO DOWNLOAD STEADILY..
That's it! Hope it helps you.
If you found other ideas feel free to share here as well.
Have a nice day!