Error when using Pachly frontend

Is anyone here using Pachly GitHub - pachli/pachli-android: The Pachli Android app on their Android devices?
I am getting the error below when starting the app:

Your server does not support this feature: Not implemented
You can continue, but your lists and filters my be incomplete

This can obviously be an issue in the app but I thought I’d start asking here before bothering the Pachly developer.
There’s nothing obvious in my logs