[Samba] Windows users can't change password 4.1.6

[Michał Półrolniczak]

Hello, 

When PDC was installed I remember that everybody could change thair passwords after first 24h after password reset via admin console. 
(I remamber that I was searching for this and even if GPO was min 0 days for changing password you had to wait) 
Anyway... Now noone is able to change password. 
When GPO tells you to change password after 30days, or you want to change it; typing old password and new one 
(something new, with few Upper and Lower chars, numbers and special char, more than 8 lenght) 
user get error about new password not being valid with GPO, but if he try to enter old password and another new 
the errors is about bad old password, the first new passwords is not working too.