My cellphone carrier is Mobilicity. Their "My Account" self-customer-service website runs an Amdocs Ltd. web application called Amdocs Multichannel Self-Service (AMSS).
Anyone can visit Mobilicity's AMSS server at <http://amss.mobilicity.ca/>, though if you're not a Mobilicity client, you can't do much.
Sometimes, when you try to sign in, the website sends you to <https://amss.mobilicity.ca/StoreChangePassLogin.do> in order to force you to change your password. I suspect this is the website's way of making sure that you change your password every X number of days.
That webpage states its rules right on it:
New password requires: 8-20 characters, at least 1 capital letter, at least 1 lower case letter and at least 1 number.
Today, the website insisted that I change my password again. I entered a password made of four digits, one uppercase letter, and three lowercase letters. This is a password which I have probably used on this website in the past, which will make it easier for me to remember it again in the future. Unfortunately, the website complained:
You have entered an invalid new password. Please try again.