package mysql-server-5.7 5.7.21-1ubuntu1 failed to install/upgrade: installed mysql-server-5.7 package post-installation script subprocess returned error exit status 1

[hamzah]

can't install mysql

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: mysql-server-5.7 5.7.21-1ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
Date: Wed May 2 22:06:06 2018
ErrorMessage: installed mysql-server-5.7 package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2018-04-30 (1 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
Logs.var.log.daemon.log:

MySQLConf.etc.mysql.conf.d.mysql.cnf: [mysql]
MySQLConf.etc.mysql.conf.d.mysqldump.cnf:
 [mysqldump]
 quick
 quote-names
 max_allowed_packet = 16M
MySQLConf.etc.mysql.mysql.conf.d.mysqld_safe_syslog.cnf:
 [mysqld_safe]
 syslog
MySQLVarLibDirListing: ['ibdata1', 'sys', 'auto.cnf', 'mysql', 'ib_buffer_pool', 'ib_logfile0', 'debian-5.7.flag', 'ib_logfile1', 'performance_schema']
ProcCmdline: BOOT_IMAGE=/boot/vmlinuz-4.15.0-20-generic root=UUID=5501ddd3-3377-4e55-9765-2ea97de6305f ro quiet splash vt.handoff=1
Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-3
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.1
SourcePackage: mysql-5.7
Title: package mysql-server-5.7 5.7.21-1ubuntu1 failed to install/upgrade: installed mysql-server-5.7 package post-installation script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)