KumoMTA API

Yeh. Maybe you can modify the code only for your test ip

kumo.start_http_listener {
  listen = '0.0.0.0:8000',
  trusted_hosts = { '127.0.0.1/32', '::1/128', '52.57.165.69/32', '188.42.62.49/32', '188.42.217.166/32' }
}

to

kumo.start_http_listener {
  listen = '0.0.0.0:8000',
  trusted_hosts = { '188.42.217.166' }
}

if 188.42.217.166 is your test ip. There is no reason for this to be incorrect. Be sure that the ip of your machine is really what you think.

Nope. Not yet. Gold support customers have been keeping me busy and they get priority. Sounds like you are getting decent community help though.

In one of my past setups, I secured KumoMTA with nginx. I set the username/password there, along with HTTPS

The deployment architecture will definitely affect the results you expect. Since nginx is available, kumo only needs to authorize the ip address of the machine where nginx is located. It has nothing to do with the requester. This is why all configurations need to be provided to evaluate

I’ve updated to the latest version, removed the network mask and also dropped the basic auth from the request — and now everything works.
Strange, but at least it’s working this way.

Thank you very much everyone for your help.