Django + Sqlite: database is locked

After a electrical failure my network database having problems

I open my login page by running the program but after, the username and password are no longer recognized

I get the error

Exception Type: DatabaseError Value Exception:

database is locked

and my function :

def main_page (request):

 state = ""
 username = password = ''
 if request.POST:
     username = request.POST.get ('username')
     password = request.POST.get ('password')

     user = authenticate (username = username, password = password)

The problem comes from this line : user =....

How can I fix this ?