Below is my AutoIt script (UI3_Authentication.au3) for handling a Windows authentication pop up.
AutoItSetOption(\"WinTitleMatchMode\",\"2\")
WinWait(\"Aut
This works with my ChromeDriver. Hope it will be helpful
WinWait("data:, - Google Chrome","","10") ; this is the name of the window, according to AUTOIT v3 window info
If WinExists("data:, - Google Chrome","") Then
WinActivate("data:, - Google Chrome") ; set control to the window for proxy authentication
Send("putUsernameHere{TAB}") ; send username and press TAB
WinActivate("data:, - Google Chrome") ; again set control to our window, in case that we have clicked somewhere else
Send("putPasswordHere{ENTER}") ; send the password and press enter
EndIf