If you are using that one -- https://hub.docker.com/r/nicolasdorier/docker-bitcoin -- and are trying to run some RPC commands then maybe you still have to take care of the following:
There are several methods to run bitcoin-cli against a running bitcoind container. The easiest is to simply let your bitcoin-cli container share networking with your bitcoind container:
$ docker run --rm --network container:bitcoind NicolasDorier/bitcoin bitcoin-cli getinfo
I use this image https://hub.docker.com/r/kylemanna/bitcoind. I tried to send json object like "{"jsonrpc": "2.0", "id":"curltest", "method": "getnetworkinfo", "params": [] }" via postman but i didn`n get response