I can't connect

[world70104]

I changed url to ""127.0.0.1:7777"" in MINACTIVITY.JAVA

IT SHOWS "FAILED TO CONNECTION"

In server, i entered
docker run -t -i -p 7777:7777 -p 80:80 --rm nginx_rtmp
It shows down error

docker: Error response from daemon: driver failed programming external connectivity on endpoint elegant_bartik (7a0d47f5322cced131a47dff9385721779baaedf429a1b7489369875646da5a2): Error starting userland proxy: Bind for 0.0.0.0:80: unexpected error (Failure EADDRINUSE).

I enter

docker run nginx_rtmp

It show not up error

Why reason?

Regards