There are potentially hundreds of reasons why a person would not receive an auto-response message from your MyChocolateOffice.com account. A few of the more general explanations are listed below.
The person typed their email address incorrectly into your capture page.
The persons email account is temporarily unavailable.
The persons email account is full and thus not accepting new emails.
The person has configured their email account to only allow responses from people they have sent emails to.
The person has configured their email account to only allow responses from people they have added to their "White List or Ham List". A "White or Ham List" is a list of email addresses that are allowed send to a person who utilizes a system as this.
The person utilizes a 3rd party email filtering system. Generally 3rd party filtering systems require MyChocolateOffice.com to fill out a form prior to the email being delivered to the person.
The email was received in the persons bulk email folder and they simply over-looked it.
The person has previously visited a MyChocolateOffice.com website and received a response.
MyChocolateOffice.com maintains an active list of emails that have bounced back to our server. If an email has bounced, we add it to our active bounce list. IE we do not send another email to this persons email address.
The person did not fill in their name when entering the MyChocolateOffice.com website. Our auto-responders are personalized, so when a name is not available, we do not send the information.