I think your main issue is, you are binding only to the localhost address, are you running geth on a remote server? or are you running it on your local machine and also running the mew_relay on the same machine?
if you are running your geth on a remote server and running the relay on your local machine id suggest changing to --rpcaddr="0.0.0.0" then try again by using your remote server ip for the host, "0.0.0.0" will bind the rpc to all available addresses on that machine.
for Setup Custom Node:
you are trying to use your ip "127.0.0.1" as https, try downloading the latest version dist-v3.4.2.zip of mew from here and open the index.html file now add a custom node by typing your URL as "http://127.0.0.1" it should work now.
Online version of mew wont work because it is on HTTPS and HTTPS wont allow you to communicate with HTTP urls. Therefore you have to download and run mew locally.
Don't forget to check the Custom checkbox instead of ETH.
let me know how it goes :)
