Keep trying to download update for my iwatch series 6 it won’t download constantly says download failed

Apple Watch will not update. 

Try the steps here to troubleshoot not being able to update: Update your Apple Watch - Apple Support 

Need more help with updating? 

Try these steps: 

Make sure that your Apple Watch is connecting properly to its charger.  

If your Apple Watch won't charge or won't turn on – Apple Support (UK)

 Restart your Apple Watch – Apple Support (UK)

 Restart your iPhone – Apple Support (UK)

Try again to update your Apple Watch. 

If the update won't start: 

Open the Apple Watch app on your iPhone. 

Tap General > Software Update. 

Delete the update file. 

Try again to update your Apple Watch. 

 if your Apple Watch says “you need more available storage to install a watchOS update.”  If your Apple Watch storage is full – Apple Support (UK)