Hi @Nick.Seddon !

 Try next steps :

Steps for Android

1. Restart the app (kill the app and remove it from the notification bar)
2. Try another network (4G or Wifi)
3. Restart your phone
4. Delete all the cache & data from the app (Data and storage, and then “Clear all”), then restart the app
5. Un-install the app and re-install the app

Steps for iOS

1. Quit and relaunch the app
2. Try another mobile (4G or Wifi)
3. Empty Smart Cache
4. Restart the phone
5. Clear the app data
6. Delete the app and reinstall it

Clearing the cache worked thank you