Problem with "Contact Form Clean and Simple"

When using Contact Form Clean and Simple, the e-mail doesn’t get sent unless I provide a second e-mail address. To get around this, I’ve added the same e-mail address twice.

I’m new at this and the problem could be on my end, however, I don’t see anything that I’ve done that would cause the problem.

Thank you,
Garland Smith

https://www.ads-software.com/plugins/clean-and-simple-contact-form-by-meg-nicholas/