What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
That code should be entered on the SMTP Account Wizard when you tried to add the email address to your Sender Emails.
Try to set it up again via Email Alerts > Notification (or whatever your email alert's name is) > Reply-To and Recipient Settings
This time, wait for the verification code to be sent to your email, then enter the code to the wizard.