Hargreaves Lansdown account connection not working

When setting up a new account connection to Hargreaves Lansdown the connection page is not working - the button at the bottom of the page continually shows a white loading symbol (see screenshot) and does not redirect to the Hargreaves Lansdown site/app to continue the connection setup.

I have tried closing and re-launching the app but this does not help.

I am using the iOS app version 2.2.1 on iOS 14.7.1 on an iPhone 11 Pro Max.

The same issue on Android, I am afraid.