For the lead notification/lead auto-responder to work properly, please make sure, you have followed the guideline mentioned below.
1. For lead autoresponder to work properly, make sure your form has an email field and mark it required. If your form does not have a email field, auto responder will not work.
2. Please make sure that the "From" field has a valid email address and make sure that the subject and content fields are not empty.