Plank not responding after changing password then relogging

After changing password then logging out and logging in ( as per the 'About me' manual test https://github.com/ubuntu-mate/qa/blob/master/manual-tests/about-me.md ) keyring dialogue came up as apparently my keyring password is now different to my login password. The keyring dialogue came up behind MATE Welcome and was unfocused even after clicking on it but I had to type in my old password in that before I could interact with the OS. After I had entered the old password everything is working except Plank (Mutiny layout) which has completely frozen and I can't interact with it.

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: plank 0.11.89-3
ProcVersionSignature: Ubuntu 5.11.0-11.12-generic 5.11.0
Uname: Linux 5.11.0-11-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu61
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: MATE
Date: Sat Mar 27 13:22:05 2021
ExecutablePath: /usr/bin/plank
InstallationDate: Installed on 2019-10-11 (532 days ago)
InstallationMedia: Ubuntu-MATE 19.10 "Eoan Ermine" - Beta amd64 (20190926.2)
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: plank
SuspiciousXErrors.txt:

UpgradeStatus: No upgrade log present (probably fresh install)
XsessionErrors:
 mate-session[8187]: WARNING: Could not launch application 'redshift-gtk.desktop': Unable to start application: Failed to execute child process “redshift-gtk” (No such file or directory)
 (process:8597): ayatana-indicator-sound-WARNING **: 13:18:45.463: volume-control-pulse.vala:745: Unable to connect to dbus server at 'unix:path=/run/user/1000/pulse/dbus-socket': Could not connect: No such file or directory
 (caja:8495): Gtk-WARNING **: 13:18:46.191: Failed to register client: GDBus.Error:org.gnome.SessionManager.AlreadyRegistered: Unable to register client