Microsoft Online Hosted Services Technical Blogs
The Microsoft Online Password Policies are listed below, which are validated during the Sign In Client password change operation. The above screenshot shows the requirements, however there is one additional requirement which is not displayed but is listed below:
If you have already changed your password within a 24 hour period but cannot remember it and cannot change your password again, based on the policy listed above, you must contact your Company's Microsoft Online IT Gen/Admin and request your password be Reset. The Password Reset operation creates a temporary password, which the IT Gen/Admin can send to you, so you can login and access the Online environment. Once you can login using this temporary password, you can then perform a Change Password operation listed above.