Having problems with advanced options in email notification

When I click advanced options in email notification the screen is blank have no idea what is happening. It is on all my forms.

We are sorry for the inconvenience this may have caused. We have experienced a temporary issue with the PDF attachment option in the email. However, our backend team has already fixed the issue and should be working fine by now. Please check again and let us know if you notice any further issue. We will be happy to take a look again.

Thank you.