Why does Android Device Manager not changes my password?
I solved the issue by installing ClockworkMod, and Aroma file manager with a sdcard, then I removed the next files:


password.keypattern.key
locksettings.db
locksettings.db-shm
locksettings.db-wal


Useful links:

HOW TO: Install ClockworkMod Recovery 6 on Galaxy S5 G900F

Remove /Bypass Lockscreen With Recovery