Cannot Authenticate to Microsoft Flow
I've signed up to an Enterprise Trial of Sign to see if it will help be gather signatures in SharePoint Online.
I sign in to Microsoft Flow, and try to add a connector, my connector is not signed in.

I hit Fix Connection which takes me to sign in to Sign:

Sign-In takes me to the Sign main page:

At no point am I seeing a handover of an auth token (or whatever is used) fro the sign in page back to Flow.
This means I cannot add the connector to Flow - I can't use it; the trial is ticking away unused.
Help?
