Form says it is sent successfully but no mail is received

I have set up a form using Contact Form 7 and it appeared to be working fine until I tried to uyse mail(2). However, even after de-activating mail(2) now nothing is working. My form says it is successfully sent, but nothing ever is received in my email. Here is the form: https://nvcja.calhans.com/training-calendars/course-registration/. And this is what is looks like on the back end:

To
[email protected]
From
[your-name] <[email protected]>
Subject
NVCJA Class Registration Submission
Additional Headers
Reply-To: [your-email]
Sender: [email protected]
Reply-To: [your-name] <[your-email]>
Message Body
From: [your-name] <[your-email]>
Subject: NVCJA Class Registration Submission

REGISTRATION INFORMATION

Training Officer’s Name: [your-name]
Training Officer’s Email: [your-email]

Class Name: [class-name]
Class Date: [class-date]
Class Time: [class-time]
Class Location: [location]

Coordinator’s Name: [coordinator-name]
Coordinator’s Email: [coordinator-email]

—————

Attendee Name: [attendee-name]
Attendee Email: [attendee-email]

—Additional Attendees—
Name: [attendee-name2]
Email: [attendee-email2]

Name: [attendee-name3]
Email: [attendee-email3]

Name: [attendee-name4]
Email: [attendee-email4]

Name: [attendee-name5]
Email: [attendee-email5]

——-

Additional Comments: [comments]

—
This e-mail was sent from a contact form on Northern Virginia Criminal Justice Training Academy (https://nvcja.calhans.com)

PLEASE HELP!