In Microsoft Exchange OWA (outlook web access) a user will attempt to change the account password and encounter an error “The password supplied does not meet the minimum security requirements”. This error happens even though the GPO Policy has password complexity disabled.
The cause of the error is the minimum password age in one or more of the applied GPOs on the OWA host.
Change the Policy for Minimum password age to 0. Then either run GPUPDATE /FORCE or just reboot the host.