Server is not healthy - setting up Dawarich iOS app

I am trying to connect my Dawarich iOS app to my self-hosted Dawarich instance. When I scan the QR code and try to enter the connection manually I get a “Server is not healthy” error and the app does not connect. I have tried using an IP address and a FQDN and each returns the same error. I have tried an http and an https connection also.

Has anyone seen this before and what was the solution?

Thanks