Error message when usiing TTS on Google Home Mini

On hassio, whenever I try to use TTS on Google Home Mini, all I get is a ‘plink’, rather than the spoken message. Checking the Developer Tool Logs, I get the following error. Can anyone help with diagnosing this?

I’ve answered my own question but will leave it here if it helps others.

I’m not sure if both these changes were required, but I know the second one definitely was.

  • I added the add-on Google Assistant SDK (I don’t think this was needed)

  • I commented out the http entries in configuration.yaml. I suspect this is where the problem was, as for a time I was using DuckDNS, which uses a Let’s Encrypt certificate, therefore making local access https and I think it is the SSL that was causing the problem. I no longer use DuckDNS, as I have Home Assistant Cloud.