PyAutoGui on non-gnome OS (Lubuntu)

Question

Here's my - very simple - code :

import pyautogui

x, y = 1321, 367 #the coordinates i want to click on

while True:
    clickcolor = (75, 219, 106) #which is the tuple of my rgb value
    if pyautogui.pixelMatchesColor(x,y,clickcolor) == True:
        pyautogui.leftClick(x,y)

So when I ran this code on Lubuntu, I got an error message that told me to install 'gnome-screenshot'. I installed it (with 'gnome-shell') on my system and when i ran the script again i got :

** Message: Unable to use GNOME Shell's builtin screenshot interface, resorting to fallback X11.

I tried to uninstall the two gnome packages and ran it again -> did'nt work I tried to install xfce screenshot package -> did'nt work (maybe i did it wrong ?) I tried the getPixel() function of pyautogui -> gave me the exact same error message

So now I am out of ideas to get my code work on my non-gnome system and i need your help

Thanks, M4elstr0m