#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)^.*:.*\K:.*$"
Local $sString = "52152525121512@gmail.com:161361361:1251136136" & @CRLF & _
"532353472626326@gmail.com:2361251251225:-" & @CRLF & _
"126125252155@gmail.com:215125151251252:135263623,13631535315" & @CRLF & _
"" & @CRLF & _
""
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