Need help with a error in my code, that i cannot see for my self! sorry as it may be me being stupid

So, i have been making my own login system, and saving it to a txt file. i have completed the basic's nearly, Login, Register, and now i am trying to add a forget password and username functions. so basically i have a if statement that checks if the user name is in one of the files. and then sends a recovery code. well for this case its a var assigned to randint(1000,9999) thats to reset the password. then i thought what if the user forgets there username, well you get them to insert there email they signed up with and if it matches a account(in one of the saved files) it sends a code to that email(console). Reset password works fine, but trying to find the players username is hard one, im not directly trying to match the email with the username, im trying to read the file for a email that matches one that is saved. and then will pull there username after, but i havent got that far yet, as when i enter a email its not finding it, instead its finding the username, could somone please help. it could be a small error i cannot see because its so late, and im so tired, but any help would be much appreciated thx.

`import tkinter
from tkinter import*
import os
import random
from random import randint

def register_user():
    username_info = username.get()
    password_info = password.get()
    email_info = email.get()

    file=open(username_info, 'w')
    file.write(username_info+'\n')
    file.write(password_info+'\n')
    file.write(email_info)
    file.close()

    username_entry.delete(0, END)
    password_entry.delete(0, END)
    email_entry.delete(0, END)

    Label(screen1, text = 'Registration susccesful', fg = 'green', font = ('calibri', 11)).pack()


def login_verify():
    username1 = username_verify.get()
    password1 = password_verify.get()

    username_entry1.delete(0, END)
    password_entry1.delete(0, END)

    list_of_files = os.listdir()

    if username1 in list_of_files:
        file1 = open(username1, 'r')
        verify = file1.read().splitlines()
        if password1 in verify:
            print('Login Sucess')
        else:
            print('password incorrect')
    else:
        print('username incorrect')
        
def codeS():
    global code
    code = randint(1000, 9999)

def submit_code():
    code1 = code_verify.get()

    password_code.delete(0, END)

    if int(code1) == code:
        Label(screen4, text='Code Correct', bg='green').pack()
    else:
        Label(screen4, text='Wrong Code', bg='red').pack()
        
def change_password():
    global code_verify
    global password_code
    code_verify = StringVar()
    
    username2 = username_verify2.get()

    username_entry2.delete(0, END)

    list_of_files = os.listdir()

    if username2 in list_of_files:
        file2 = open(username2, 'r')
        verify1 = file2.read().splitlines()
        codeS()
        print(code)
        Label(screen4, text='Reset Code Sent').pack()
        password_code = Entry(screen4, textvariable = code_verify)
        password_code.pack()
        Label(screen4, text='').pack()
        Button(screen4, text='Submit Code', width = 10, height = 2, command=submit_code).pack()
    else:
        Label(screen4, text='').pack()
        Label(screen4, text='No matching user name').pack()

def find_username1():
    global code_verify2
    global username_code
    code_verify2 = StringVar()

    email2 = email_verify1.get()

    email_entry1.delete(0, END)

    list_of_files = os.listdir()

    if email2 in list_of_files:
        file3 = open(email2, 'r')
        verify3 = file3.read().splitlines()
        print('found')
    else:
        Label(screen5, text='').pack()
        Label(screen5, text='No matching email').pack()

def register():
    global screen1
    screen1 = Toplevel(screen)
    screen1.title('Register')
    screen1.geometry('300x250')

    global username
    global password
    global email
    global username_entry
    global password_entry
    global email_entry

    username = StringVar()
    password = StringVar()
    email = StringVar()
    
    Label(screen1, text = 'Please enter details bellow').pack()
    Label(screen1, text = '').pack()
    Label(screen1, text = 'Username *').pack()
    username_entry = Entry(screen1, textvariable = username)
    username_entry.pack()
    Label(screen1, text = 'Password *').pack()
    password_entry = Entry(screen1, textvariable = password)
    password_entry.pack()
    Label(screen1, text = 'Email *').pack()
    email_entry = Entry(screen1, textvariable = email)
    email_entry.pack()
    Label(screen1, text = '').pack()
    Button(screen1, text = 'Register', width = 10, height = 1, command = register_user).pack()

def reset_password():
    global screen4
    screen4 = Toplevel(screen)
    screen4.title('Reset Password')
    screen4.geometry('300x250')
    Label(screen4, text='Enter username *', height = 2, width = 30).pack()

    global username_entry2
    global username_verify2

    username_verify2 = StringVar()

    username_entry2 = Entry(screen4, textvariable = username_verify2)
    username_entry2.pack()

    Label(screen4, text='').pack()

    Button(screen4, text='Reset Password', command=change_password).pack()

def forgot_user():
    global screen5
    screen5 = Toplevel(screen)
    screen5.title('Find Username')
    screen5.geometry('300x250')
    Label(screen5, text='Enter Email *', height=2, width=30).pack()

    global email_entry1
    global email_verify1

    email_verify1 = StringVar()

    email_entry1 = Entry(screen5, textvariable = email_verify1, width=30)
    email_entry1.pack()

    Label(screen5, text='').pack()

    Button(screen5, text='Find Username', command=find_username1).pack()

def login_issue():
    global screen3
    screen3 = Toplevel(screen)
    screen3.title('Login Issues')
    screen3.geometry('350x250')
    Label(screen3, text='Have you forgot your username or password?', bg = 'grey', width = '350', height = '2', font = ('Calibri', 13)).pack()
    Label(screen3, text = '').pack()

    Button(screen3, text = 'Username', width = 30, height = 2, command = forgot_user).pack()
    Label(screen3, text = '').pack()
    Button(screen3, text = 'Password', width = 30, height = 2, command = reset_password).pack()

    
def login():
    global screen2
    screen2 = Toplevel(screen)
    screen2.title('Login')
    screen2.geometry('300x250')
    Label(screen2, text = 'Please enter details bellow to login').pack()
    Label(screen2, text = '').pack()

    global username_verify
    global password_verify

    username_verify = StringVar()
    password_verify = StringVar()

    global username_entry1
    global password_entry1

    Label(screen2, text = 'Username * ').pack()
    username_entry1 = Entry(screen2, textvariable = username_verify)
    username_entry1.pack()
    Label(screen2, text = '').pack()
    Label(screen2, text = 'Password * ').pack()
    password_entry1 = Entry(screen2, textvariable = password_verify)
    password_entry1.pack()
    Label(screen2, text = '').pack()
    Button(screen2, text = 'Login', width = 10, height = 1, command = login_verify).pack()
    Label(screen2, text = '').pack()
    Button(screen2, text = 'Login issue?', width = 10, height = 1, command=login_issue).pack()
    

def main_screen():
    global screen
    screen = Tk()
    screen.geometry('300x250')
    screen.title('Login API 1.2')
    Label(text = 'Login 1.2', bg = 'grey', width = '300', height = '2', font = ('Calibri', 13)).pack()
    Label(text = '').pack()
    Button(text = 'Login', height = '2', width = '30', command=login).pack()
    Label(text = '').pack()
    Button(text = 'Register', height = '2', width = '30', command=register).pack()

    screen.mainloop()
main_screen()

`

The relevant entry point is find_username1() in the supplied script; compare its lookup with register_user(), which writes the username, password, and email into files named by username. Run the forgot-username flow with a registered account and make the completed behavior identify the username associated with the entered email.