TypeError: can only join an iterable

from sqlite3 import *
from tkinter import *
 
con = connect("BASA.db")
cur = con.cursor()
stud = [
    ('Вячеслав',),
    ('Владислав',),
    ('Ярослав',),
]
 
#cur.execute("create table students(id, name)")
cur.executemany("insert into students values (null, ?)", stud)
cur.execute("SELECT name FROM Students ORDER BY name LIMIT 5")
print(cur.fetchone())
print(cur.fetchone())
print(cur.fetchone())
 
def fav_stud():
    c = ['Error 404']
    n = int(enter.get())
    cur.execute("SELECT name FROM Students ORDER BY name")
    for i in range(0, n):
        s = cur.fetchone()
        name['text'] = ' '.join(s)
        if n > 3:
            name['text'] = ' '.join(c)
            
 
window = Tk()
window.title('BD')
window.geometry('200x100')
lab = Label(text='Name')
enter = Entry(width=20)
name = Label(width=30, fg='lime')
but = Button(window,text="Вывести", command = fav_stud)
 
enter.grid(column=1, row=1)
but.grid(column=1, row=4)
lab.grid(column=1, row=2)
name.grid(column=1, row=3)
 
window.mainloop()
con.close()

def fav_stud():
    c = ['Error 404']
    n = int(enter.get())
    cur.execute("SELECT name FROM Students ORDER BY name")
    for i in range(0, n):
        s = cur.fetchone()
        name['text'] = ' '.join(s)
        if n > 3:
            name['text'] = ' '.join(c)
            return