Ubuntu – Active Directory users unable to change passwords [SSSD]

I've set up an Ubuntu 16.04 system to join a AD domain following the instruction set here.

I can login with AD users and everything is working correctly there, however AD users are unable to change their passwords either with passwd or kpasswd. I'm not sure what I might not have configured correctly.

Here are my configuration files:

== /etc/pam.d/common-password ==

password        sufficient                      pam_sss.so
password        required                        pam_cracklib.so retry=6 minlen=9 difok=1 ucredit=-1 lcredit=-1 dcredit=-1 ocredit=-1 enforce_for_root
password        [success=1 default=ignore]      pam_unix.so obscure try_first_pass sha512
password        requisite                       pam_deny.so
password        required                        pam_permit.so
password        optional        pam_gnome_keyring.so

== /etc/sssd/sssd.conf ==

[sssd]
domains = my.domain.com
config_file_version = 2
services = nss, pam

[domain/my.domain.com]
ad_domain = my.domain.com
krb5_realm = my.domain.com
realmd_tags = manages-system joined-with-adcli
cache_credentials = True
id_provider = ad
krb5_store_password_if_offline = True
default_shell = /bin/bash
ldap_id_mapping = True
use_fully_qualified_names = False
fallback_homedir = /home/%d/%u
access_provider = ad

auth_provider = ad
chpass_provider = ad
ldap_schema = ad
dyndns_update = true
dyndsn_refresh_interval = 43200
dyndns_update_ptr = true
dyndns_ttl = 3600
krb5_use_enterprise_principal = false

Any help would be greatly appreciated. I've been googling for several hours no with no luck…

EDIT:
Here's what I'm seeing in the terminal:

cypher@ubuVB2:~$ passwd
Current Password: 
New Password: 
Reenter new Password: 
Password change failed. Server message: Please make sure the password meets the complexity constraints.
New password: 
Retype new password: 
passwd: Authentication token manipulation error
passwd: password unchanged

I'm certain that the password I'm trying to set meets the complexity requirements, so this is rather odd…