Can't connect to my Nextcloud server in iOS Files app

I’m trying to connect to my Nextcloud server in the iOS Files app and getting the following message: “There was a problem connecting to the server. Check the server name or IP address, and then try again. If you continue to have problems, contact your system administrator.” (I am running a personal setup, and I am the system administrator…)

Basic details:

  • Nextcloud v22.2.3
  • iOS v15.2, running on iPad mini (6th gen)
  • using iOS Nextcloud app with no problems

To troubleshoot, I also tried to connect to a demo Nextcloud account (via https://try.nextcloud.com) - I confirmed that I can connect to it via web browser, but it also fails in the same way when trying to connect via the iOS Files app.

Is there a step in the setup I’m missing, or is the current iOS version not yet supported?