I dont have users in sysadmin except [sa] user
unfortunately, I logged in as [sa] user and disabled it
then I cant enable it, what I can do to enable it again?
You'll have to use sqlcmd.exe
with Windows Authentication (Specify the -E flag)
and renable the account:
Open up command prompt and navigate to the SQL Directory
and use sqlcmd.exe -S server -E
USE [YourDatabase]
GO
ALTER LOGIN [sa] ENABLE
GO