How to correct the following one player tictactoe game?

Question

I have made the following tic tac toe game which reads the current state of the board, stores it in entries, then I read a text file which has data in the format XOXXXO O:6where the part after : is the number of box the AI should choose on the basis of the part before the : so that the AI never loses. For some reason, it kinda stops working after my 3rd input.

main function

global win
    global boxsize
    entries = [[None] * 3, [None] * 3, [None] * 3]

    windowsize = 300
    boxsize = 100

    win = GraphWin("Tic Tac Toe", windowsize, windowsize, autoflush=False)

    for i in range(2):
        hline = Line(Point(0, (windowsize / 3) * (i + 1)), Point(windowsize, (windowsize / 3) * (i + 1)))
        hline.draw(win)
        vline = Line(Point((windowsize / 3) * (i + 1), 0), Point((windowsize / 3) * (i + 1), windowsize))
        vline.draw(win)

    for i in range(1, 10):

        print("Player 1: click a square.")
        p1mouse = win.getMouse()
        p1x = p1mouse.getX()
        p1y = p1mouse.getY()
        tic_tac_toe_X(entries, win, p1x, p1y)
        if (check(entries) == True):
            print("Player 1 is the winner.")
            break

        tic_tac_toe_O_ai(entries, win)
        if (check(entries) == True):
            print("Player 2 is the winner.")
            break

    print("Enter 1 to play again, 0 to Exit : ")
    x = int(input())
    if (x == 1):
        win.close()
        main()
    else:
        sys.exit()

Function that reads the text file and returns the box number move for the AI

Reads the .txt file to get the box number to move to

def ai_move(entries):

    df = pd.read_csv("Dataset.txt", sep=":", names=['strings', 'moves'])
    a = df[['strings']]
    b = df[['moves']]
    status = a.to_numpy()
    next_move = b.to_numpy()
    status = status.flatten()
    next_move = next_move.flatten()

    str = ""
    for i in range(3):
        for j in range(3):
            if entries[i][j] == 'x':
                str += "X"
            elif entries[i][j] == 'o':
                str += "O"
            else:
                str += " "

    for i in range(2112):
        if str == status[i]:
            next = int(next_move[i])
            return next

function that prints the 'O' for the AI

# Draws the 'O' for the AI

def tic_tac_toe_O_ai(entries, win):

    box = ai_move(entries)
    if (box == 0):
        center = Point(50, 50)
        entries[0][0] = 'o'
    elif (box == 1):
        center = Point(150, 50)
        entries[1][0] = 'o'
    elif (box == 2):
        center = Point(250, 50)
        entries[2][0] = 'o'
    elif (box == 3):
        center = Point(50, 150)
        entries[0][1] = 'o'
    elif (box == 4):
        center = Point(150, 150)
        entries[1][1] = 'o'
    elif (box == 5):
        center = Point(250, 150)
        entries[2][1] = 'o'
    elif (box == 6):
        center = Point(50, 250)
        entries[0][2] = 'o'
    elif (box == 7):
        center = Point(150, 250)
        entries[1][2] = 'o'
    elif (box == 8):
        center = Point(250, 250)
        entries[2][2] = 'o'

    circle = Circle(center, 50)
    circle.setOutline('green')
    circle.setWidth(5)
    circle.draw(win)