In the Server Manager click on Tools and from the drop down click Group Policy Management
- Expand Forrest >> Domains >> Your Domain Controller.
 - Right click on the Default Domain Policy and click on the Edit from the context menu.
 - Now Expand Computer Configuration -> Policies -> Windows Settings -> Security Settings -> Account Policies -> Password Policy
 - Double-click on the Passwords Must Meet Complexity Requirements option in the right pane.
 - Select Disabled under define this policy setting:
 - Click Apply then OK all the way out and close the GPO window.