Hotkey with simple colon ":" autohotkey

Why my script isn't working ?

<^>!:::
{
    MsgBox You pressed AltGr+:
    Return
}

Answer

What kind of keyboard layout do you use? If I want to get to :, I have to use Shift+;.

I can't use RAlt on my PC, but this works for me with the LAlt key:

!+`;:: ; Use + to shift the [;] key into [:] and use a back-tick [`] to literally interpret the next character.
{
    MsgBox You pressed [LAlt]+[:]
    Return
}