Hey, thanks for reading. Glad you enjoyed the article. Were you able to resolve the issue? Sorry it took me so long to get back.
Judging by the error, it looks like the users table no longer exists and needs to be created.
If you're not very familiar with inspecting databases with python, i recommend checking out and trying the program db browser. That program gives you a gui to inspect and manipulate the sqlite file using raw sql.
Otherwise, from the article, the Create the Users Table section references the code you likely need to run so the database is correctly set up in the table.
conn = sqlite3.connect('data.sqlite')
#connect to the database
engine = create_engine('sqlite:///data.sqlite')
db = SQLAlchemy()
#class for the table Users
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(15), unique=True, nullable = False)
email = db.Column(db.String(50), unique=True)
password = db.Column(db.String(80))
Users_tbl = Table('users', Users.metadata)
#fuction to create table using Users class
#create the table
Hopefully these tips help.