Unable to renew authorisation token

Hi,

I tried to use the plugin a while back but could never get a feed to show. I gave up but have just tried again and my Access token has expired. I’ve clicked the regenerate button and sign in with an admin account for the company but it just comes straight back to the plugin settings page with the error still there.

I was originally able to get a token but never a feed and I suspect the two issues are related but I don’t know how.

I have tried removing the plugin and reinstalling but all settings were saved and no change.
I have created a new app and used fresh details but with the same result.

Any ideas?