My Apple Watch was streaming fine over LTE and would switch from my phone e connection to the LTE connection as I left home. Yesterday it failed to connect and posted “something went wrong. Try again later” 

After looking for solutions I have 

-  restarted my watch 

- unpaired and updated my headphones 

- Reset watch (which takes an hour) 

- done a clean delete and reinstall of Spotify 

Through one of these phases I got the flashing white watch icon - but no connection. 

Now I don’t get the option to switch device to my watch and only have phone and Sonos options. 

My headphones are pairing fine with my watch. My LTE is working fine. 

it’s frustrating when everything was working fine and then you left spending hours trying to fix a problem you can’t identify. 

device Apple Watch 6SE version watchOS  7.5 / ios14.6 / Spotify 8.6.30