#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "^((([A-Za-z][A-Za-z0-9]*[\.\_]*[A-Za-z0-9]+){0,30}@[a-z]{3,15}\.[a-z]{2,5})|(([A-Za-z][A-Za-z0-9]*[._]*[A-Za-z0-9]+){0,30}@[a-z]{3,15}\.[a-z]{2}\.[a-z]{2,5}))$"
Local $sString = "lkffdsl@gmail.co.co"
Local $sSubst = ""
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm