Can't connect iOS app to HomeAssistant: Error: Invalid client id or redirect uri

Hello, I can’t connect Home Assistant to the iOS app.

I’m running Home Assistant 0.97.2 on my Mac. I disabled ipv6 and I use DuckDNS to get a domain with Let’s Encrypt HTTPS.

I get the following error:

The log shows the following:

2019-08-26 16:54:15 ERROR (MainThread) [homeassistant.components.auth.indieauth] OS error while looking up redirect_uri No route to host
2019-08-26 16:54:15 WARNING (MainThread) [homeassistant.components.http.ban] Login attempt or request with invalid authentication from