package phpmyadmin 4:4.6.6-5 failed to install/upgrade: installed phpmyadmin package pre-removal script subprocess returned error exit status 1

[South Soft]

#2006 - MySQL server has gone away;

mysqli_real_connect(): Unexpected server respose while doing caching_sha2 auth: 109;

mysqli_real_connect(): MySQL server has gone away;

mysqli_real_connect(): (HY000/2006): MySQL server has gone away;

i have mysql-server installed but it showing this error..

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: phpmyadmin 4:4.6.6-5
ProcVersionSignature: Ubuntu 4.15.0-43.46-generic 4.15.18
Uname: Linux 4.15.0-43-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
AptOrdering:
 phpmyadmin:amd64: Remove
 NULL: ConfigurePending
Architecture: amd64
Date: Mon Jan 21 10:26:49 2019
ErrorMessage: installed phpmyadmin package pre-removal script subprocess returned error exit status 1
InstallationDate: Installed on 2019-01-02 (18 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
PackageArchitecture: all
Python3Details: /usr/bin/python3.6, Python 3.6.7, python3-minimal, 3.6.7-1~18.04
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.3ubuntu0.1
SourcePackage: phpmyadmin
Title: package phpmyadmin 4:4.6.6-5 failed to install/upgrade: installed phpmyadmin package pre-removal script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)