"psql: could not connect to server: Connection refused" Error when connecting to remote database

I am trying to connect to a Postgres database installed in a remote server using the following command:

psql -h host_ip -U db_username -d db_name

This is the error that occurs:

psql: could not connect to server: Connection refusedIs the server running on host "<host_ip>" and acceptingTCP/IP connections on port 5432?

1. Postgres installed version is 9.4.
2. Host operating system: Ubuntu 15.04
3. Client operating system: Centos 7

I already tried the following but the issue remains unresolved:

1. Edited pg_hba.conf file to include

host all all 0.0.0.0/0 md5

2. Edited 'postgresql.conf' and changed the listen parameter to

listen_addresses='*'

3. Restarted Postgres service.
4. Disabled firewall and iptables on host and client.
5. I checked by running the psql command locally and it worked.
6. I tried the second solution given in this question. Running nmap gave me the following output:

Starting Nmap 6.47 ( http://nmap.org ) at 2015-09-07 18:08 IST Nmap scan report for 10.17.250.250 Host is up (0.0000040s latency). Not shown: 997 closed ports PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 80/tcp open http

Am I missing something? Hope someone can help.