Oddly enough I did not receive Ricardo Martin Gomez's response directly -- just received it with Ron's response.
Regarding:

> You must be check postgres.conf file in order to see the particular port.
> Sometimes postgres is running but in another port 5433, 5434, etc.
Where do I find that postgres. conf file; where and how do I look? (I have tried plenty of searching and trying what's suggested, to no avail.)

Not sure what to do with this, so I'll keep it in mind for future reference:

 > By default???

-----Original Message-----
From: Ron
Sent: Nov 24, 2018 1:10 PM
To: "pgsql-admin@lists.postgresql.org"
Subject: Re: could not connect to server, in order to operate pgAdmin/PostgreSQL

By default???

On 11/24/2018 06:16 AM, Ricardo Martin Gomez wrote:
Hello,
You must be check postgres.conf file in order to see the particular port.
Sometimes postgres is running but in another port 5433, 5434, etc.


From: Ron <ronljohnsonjr@gmail.com>
Sent: Saturday, November 24, 2018 3:25:02 AM
To: pgsql-admin@lists.postgresql.org
Subject: Re: could not connect to server, in order to operate pgAdmin/PostgreSQL
 
On 11/23/2018 08:31 PM, Anne Marie Harm wrote:
Hello, 

Unfortunately I'm unable to operate pgAdmin/PostgreSQL; first of all I can only install version 9.5 (tried versions 11, 10, and 9.6 -- but cannot install).

How come.  (Are you running a really old distro version?)

When I launch pgAdmin in order to try to use PostgreSGL 9.5, here is the full text of the error message I receive (also, screenshot attached):

could not connect to server: Connection refused (0x0000274D/10061) Is the server running on host "localhost" (::1) and accepting TCP/IP connections on port 5432? could not connect to server: Connection refused (0x0000274D/10061) Is the server running on host "localhost" (127.0.0.1) and accepting TCP/IP connections on port 5432?

Well, is Postgres running?  You installed Pg but did you start it?  These two commands will tell you:

pg_ctl status # when logged in as user postgres
sudo netstat -an | grep 5432

--
Angular momentum makes the world go 'round.

--
Angular momentum makes the world go 'round.
 

----------------------------
Anne Marie Harm
(312) 563-9397
amharm@earthlink.net
https://www.linkedin.com/in/annemarieharm/



----------------------------
Anne Marie Harm
(312) 563-9397
amharm@earthlink.net
https://www.linkedin.com/in/annemarieharm/



----------------------------
Anne Marie Harm
(312) 563-9397
amharm@earthlink.net
https://www.linkedin.com/in/annemarieharm/