Sorry, connecting to HTTPS is not supported on this platform. Please, use WebUI to disable HTTPS try again.

I get an error message on startup: “Sorry, connecting to HTTPS is not supported on this platform. Please, use WebUI to disable HTTPS try again.”

What does this mean?

Is it safe to disable HTTPS?

Why is this happening now when it never happened before?

Update: In the settings the HTTPS for GUI setting is unset anyway, and I can’t find any other HTTPS related settings. Help?