Synaptic hangs and not opening both from application launcher or from command line

[MURLI GOPAL KRISHNAMOORTY]

From command launcher no pop up GUI after double clicking the synaptic icon.
From command line
$ sudo synaptic
No protocol specified
Unable to init server: Could not connect: Connection refused

(synaptic:9803): Gtk-WARNING **: cannot open display: :0
Tried uninstall reinstall, but of no use.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: synaptic 0.84.2
ProcVersionSignature: Ubuntu 4.13.0-17.20-generic 4.13.8
Uname: Linux 4.13.0-17-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.5
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Nov 30 12:37:47 2017
InstallationDate: Installed on 2017-11-30 (0 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
ProcEnviron:
 LANGUAGE=en_IN:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_IN
 SHELL=/bin/bash
SourcePackage: synaptic
UpgradeStatus: No upgrade log present (probably fresh install)