502 when redirecting from one caddy to another

So I have a Master caddy which redirects to another servers inside the LAN.

The current configuration of the Master is like the following:

http://example.com {
    proxy / http://192.168.1.153:80 {
        transparent
    }
}

https://example.com {
    proxy / https://192.168.1.153:443 {
        transparent
    }
}

And the configuration of the caddy at 192.168.1.153 is the following:

http://example.com, https://example.com {
    root /example.com
}

http://example.com works fine but https://example.con gives 502 Bad Gateway.

If i use insecure_skip_verify I receive 403... And I don't want to use it anyway.

Both 80 and 443 are open on the router and redirecting to the Master caddy. There must be something wrong with my configuration but I cannot see what is it.

PD

I have tried:

192.168.1.153:443

https://192.168.1.153

None seem to work.

Updated with solution

http://example.com {
    redir https://{host}{uri}
}

https://example.com {
    proxy / 192.168.1.153:80 {
        transparent
    }
}

This also redirects 80 to 443, but the catch is that the "slave" on 192.168.1.153 must respond on port 80, not on 443. Because the 80 gets "upgraded" to 443 on the master caddy.

Of course that will not work. You have at least 2 servers each with a different IP. So, let me explain it to you.

One server has its IP binded to the dns example.com so it is ok for its Caddyfile to listen at http://example.com. Also, this caddyfile redirects to the server with the IP 192.168.1.153 (the second server).

The second server neither has the dns example.com binded to its IP nor should it listen at that dns. Instead you should change its listerner at its IP or just define the port. Here is how the second caddyfile should look like.

:80 {
  tls off
  root /example.com
}

Regarding enabled SSL You are not assigning certificates for SSL so it does not make sense to add https:// or even listeners at 443. Keep it in http until you get certificates.