BUG #16086: Cannot connect using psql, however I can connect using pgadmin

The following bug has been logged on the website:

Bug reference:      16086
Logged by:          Muziwandile Zwane
Email address:      mzwai99@outlook.com
PostgreSQL version: 12.0
Operating system:   Linux x86-64
Description:

[root@zardplpsmasdev01 ~]# systemctl status postgresql-12 -l
● postgresql-12.service - PostgreSQL 12 database server
   Loaded: loaded (/usr/lib/systemd/system/postgresql-12.service; enabled;
vendor preset: disabled)
   Active: active (running) since Tue 2019-10-29 10:59:59 SAST; 45s ago
     Docs: https://www.postgresql.org/docs/12/static/
  Process: 98621 ExecStartPre=/usr/pgsql-12/bin/postgresql-12-check-db-dir
${PGDATA} (code=exited, status=0/SUCCESS)
 Main PID: 98628 (postmaster)
    Tasks: 8
   Memory: 18.1M
   CGroup: /system.slice/postgresql-12.service
           ├─98628 /usr/pgsql-12/bin/postmaster -D
/u01/postgress/pgsql/12/data/
           ├─98629 postgres: logger
           ├─98631 postgres: checkpointer
           ├─98632 postgres: background writer
           ├─98633 postgres: walwriter
           ├─98634 postgres: autovacuum launcher
           ├─98635 postgres: stats collector
           └─98636 postgres: logical replication launcher

Oct 29 10:59:59 zardplpsmasdev01 systemd[1]: Starting PostgreSQL 12 database
server...
Oct 29 10:59:59 zardplpsmasdev01 postmaster[98628]: 2019-10-29 10:59:59.483
SAST [98628] LOG:  starting PostgreSQL 12.0 on x86_64-pc-linux-gnu, compiled
by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39), 64-bit
Oct 29 10:59:59 zardplpsmasdev01 postmaster[98628]: 2019-10-29 10:59:59.486
SAST [98628] LOG:  listening on IPv4 address "0.0.0.0", port 5437
Oct 29 10:59:59 zardplpsmasdev01 postmaster[98628]: 2019-10-29 10:59:59.486
SAST [98628] LOG:  listening on IPv6 address "::", port 5437
Oct 29 10:59:59 zardplpsmasdev01 postmaster[98628]: 2019-10-29 10:59:59.495
SAST [98628] LOG:  listening on Unix socket
"/u01/postgresql/.s.PGSQL.5437"
Oct 29 10:59:59 zardplpsmasdev01 postmaster[98628]: 2019-10-29 10:59:59.505
SAST [98628] LOG:  listening on Unix socket "/tmp/.s.PGSQL.5437"
Oct 29 10:59:59 zardplpsmasdev01 postmaster[98628]: 2019-10-29 10:59:59.522
SAST [98628] LOG:  redirecting log output to logging collector process
Oct 29 10:59:59 zardplpsmasdev01 postmaster[98628]: 2019-10-29 10:59:59.522
SAST [98628] HINT:  Future log output will appear in directory "log".
Oct 29 10:59:59 zardplpsmasdev01 systemd[1]: Started PostgreSQL 12 database
server.
[root@zardplpsmasdev01 ~]# su - postgres -c "psql"
psql: error: could not connect to server: could not connect to server: No
such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket
"/var/run/postgresql/.s.PGSQL.5432"?
[root@zardplpsmasdev01 ~]#