plex install error on 16.04

Job for mysql.service failed because the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details.
invoke-rc.d: initscript mysql, action "start" failed.
dpkg: error processing package mysql-server-5.7 (--configure):
 subprocess installed post-installation script returned error exit status 1
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          dpkg: dependency problems prevent configuration of mysql-server:
 mysql-server depends on mysql-server-5.7; however:
  Package mysql-server-5.7 is not configured yet.


dpkg: error processing package mysql-server (--configure):
 dependency problems - leaving unconfigured
Setting up plexmediaserver (0.9.16.4.1911-ee6e505-debian) ...
plex user exists now checking for group
Group plex exists proceeding with installation
Plex Media Server is not running (no process found)...
Starting Plex Media Server: done
Errors were encountered while processing:
 mysql-server-5.7
 mysql-server