I've had an ongoing issue for a couple of days now and it's getting annoying! I use Windows 10 and I've had Spotify for a while; it's been running smoothly.
The other day I turned on my laptop and Spotify said it was "offline" even though I had perfectly good internet connection and everything else was working. I tried logging out and back in, turning my laptop on and off. Nothing worked. I decided to reinstall Spotify and that didn't work either.
Today when it said "offline", I tried to reinstall again and this time it would not allow me to log in. It said it was Error 101 and a firewall was preventing Spotify from running. I had a look through the forums and followed instructions, added it to my firewall allowance lists, etc. and nothing is working.