host    all             all             192.168.4.1/24       md5

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
    s.connect(('localhost', 5432))
    s.close()
    messagebox.showinfo("working", "postgres is connected")
except socket.error as ex:
    messagebox.showinfo("error","Connection failed with errno {0}: {1}".format(ex.errno, ex.strerror))
    messagebox.showinfo("error", "database is not connected")

import psycopg2
from tkinter import *
from tkinter import messagebox

def func():

    try:

        con = psycopg2.connect("dbname='MAIN_TEST' user='postgres' host='localhost' password='postgres123' port='5432'")
        cur = con.cursor()
        cur.execute("SELECT * FROM PROFILE")
        rows = cur.fetchall()
        for row in rows:
            messagebox.showinfo("DATA FETCHED", row)

    except psycopg2.OperationalError as ex:
        messagebox.showinfo("ERROR","Connection failed: {0}".format(ex))
        messagebox.showinfo("ERROR", "cant connect to the database")

root = Tk()

b = Button(text="FETCH DATA", command=func)
b.place(x=100, y=100)

root.mainloop()