I suspect the issue is that without the frontend either the api or the wesockets event stream are not being enabled - AD needs both.
just out of curiosity:
what do you gain by disabeling the frontend?
i dont use the frontend very much, and i can see a time that i could do without it at all, but i dont see a big advantage by disabeling it.
I use Nginx as a reverse proxy.
@gpbenton Thank you! That was it. 
@ReneTode I’m doing a project in which the HA frontend is not needed, instead, I have created a frontend with appdaemon and Telegram so I don’t see why it should it be running if it’s not needed. In my case I’m using homeassistant as a slave and appdaemon as a master.
I see your point now after I did a docker stat on a container with and without the frontend. I had forgotten that the frontend was merely serving a static file to the browser.
Thanks for your help, sorry for wasting your time.
if my time wasnt helping you then it probably helped another that reads this.
an any case it wasnt wasted 