When we release a new version of Form Publisher, new permissions might be added. If you do not reauthorize Form Publisher, then the add-on will stop working (including files generation, sending emails etc.).
Form Publisher will send you an email to inform you about this new authorization:
What you have to do next is to open your Google Form, go to Form Publisher through the add-on menu, then click on 'Form Publisher Status':
A new window will pop up, click on 'Allow' to accept the new permissions: