An error message saying "An internal error occurred. Please contact support." would be displayed when you are trying to edit the email notifications by signing up with an email address from a generic domain such as gmail.com or outlook.com. In such cases, you would be able to edit the email notifications only if there are more than 10 tickets created in your account.
If you continue to face further issues, please drop in an email to email@example.com with your Freshdesk URL and we'll have this sorted for you.