Garmin Connect App not opening

My previous garmin watch broke so I didn't use the Connect app for around 3 months. I have now bought a new Garmin watch but when I open my Connect App to load my new watch, it won't load or open - the running symbol just continues to run. I have closed the app, deleted the app, redownloaded it, tried turning my phone off and on but it will not open so I am unable to wear my new watch.

Has anyone had this happen to them and what was your solution if I have tried all of the following? 

Cheers