Do the command to view your Domain Password Policy requirments:
1) vastool -u host/ info adsecurity
Password must meet complexity requirements is set to true.
The password must meet the following minimum requirements when they are changed or created:
Not contain the user's entire Account Name or entire Full Name. The Account Name and Full Name are parsed for delimiters: commas, periods, dashes or hyphens, underscores, spaces, pound signs, and tabs. If any of these delimiters are found, the Account Name or Full Name are split and all sections are verified not to be included in the password. There is no check for any character or any three characters in succession.
Contain characters from three of the following five categories:
English uppercase characters (A through Z)
English lowercase characters (a through z)
Base 10 digits (0 through 9)
Non-alphabetic characters (for example, !, $, #, %)
A catch-all category of any Unicode character that does not fall under the previous four categories. This fifth category can be regionally specific.