Windows AD PROBLEM

I have AST 606T
i already join domain with Windows AD in Asustor
but when i want to login NAS via web browser using AD account, it always say incorrect
i already checked domain user and all AD account already shown there
i also try to access file directory NAS using file explorer in Windows 7, and when i ask to enter the credential, i use AD account
and IT CAN ENTER without no problem
why the problem only on login via web browser
PLEASE HELP As soon as possible
Thanks
BTW, im using Windows AD in Windows Server 2012
is it compatible with Asustor ?
cause when i check the manual, they using Windows Server 2008 ..
i already join domain with Windows AD in Asustor
but when i want to login NAS via web browser using AD account, it always say incorrect

i already checked domain user and all AD account already shown there
i also try to access file directory NAS using file explorer in Windows 7, and when i ask to enter the credential, i use AD account
and IT CAN ENTER without no problem
why the problem only on login via web browser

PLEASE HELP As soon as possible
Thanks
BTW, im using Windows AD in Windows Server 2012
is it compatible with Asustor ?
cause when i check the manual, they using Windows Server 2008 ..