ValueError: View function did not return a response in flask [duplicate]

Answer 1

The log() method does not return a response if you're accessing it via GET. Your question is a bit uninformative where the error is happening, but this is what I can deduce.

Edit: Looking into the video, it is indeed the log method that is causing you trouble. You've accidentally indented too deep.

@app.route('/log', methods=['GET','POST'])
def log():
    error = None
    if request.method == "POST":
        if request.form['username'] != 'admin' or  request.form['password'] != 'admin':
            error = "Invalid credentials"
        else: 
            session['logged_in'] = True
            return redirect (url_for('hello'))
    return render_template('log.html', error=error)