Configure proxy on mac
Auto Proxy Discovery works either via DHCP or via DNS queries to find out where to fetch a special file called "wpad.dat" or "proxy.pac".

Further reading: Web Proxy Auto-Discovery Protocol

Neither your localhost nor the remote AWS instance is configured as valid proxy in your DHCP or DNS-server (if you run any of them at all - most routers don't count because you can't configure DHCP options and/or it's only a DNS-proxy server).

You have to configure the proxy manually - either in the browser settings or in System Preferences > Network > choose interface > Advanced... > Proxies.