Garmin forerunner 245 music no longer connecting to mobile

Hi there,

I've had my Garmin forerunner 245 music for about 1 year and 3 weeks. Unfortunately it stopped working for me 10 days ago. I was downloading a spotify playlist and before a run and it just had turned to the garmin triangle and looked stuck. I couldn't get it off this screen so had to do a factory reset on the watch. 

Upon factory reset it asks me to select language and pair to a device. I had to remove the device from Garmin connect and try to re-add it for the connection. The phone (ios mobile) detects the watch and connects but stays in a state for a long time where the watch says "Go to mobile app to add device" and the phone says "Connecting your Forerunner 245 music" with a progress bar that makes no progress. Then the phone says pairing fails.

The watch seems fine however and I tried connecting it to garmin connect on my dads phone (logged into my account) and that did work. I'm not sure what's going on but the watch seems fine, I have the latest iphone and the app works. I've uninstalled and reinstalled the app. Is there a bad state on my account/device that I can get past or any guides I can follow to help?