Caddy in docker blocked accessing other docker containers

Really not sure why we are being told we can not use paths from an external IP to be proxied when this is exactly what it is meant to do?

There is even a WIKI how to do exactly what I am asking from one of the authors of Caddy Matt Holt describing precisely what I am attempting to do.

I can’t really understand why this is no longer meant to be done as it “subfolders” and will break the paths - yet this wiki describes exactly that.

Just trying to wrap my head around why we are meant to use sub domains now and not paths - and why paths wont work etc

How has this changed ?

Is there an alternative system that I could approach this with?

Thanks in advance.