Contact Form 7 not sending emails- no confirmation, no error

I’ve noticed that Contact Form 7 recently stopped working, despite my not having touched any of the settings. What’s odd is that I receive neither a confirmation nor an error message; I click “send” and nothing happens. This problem persists across FF, Safari, and Chrome.

I read in other, older threads that it could be something to do with SMTP settings, but as the threads were 2 years old, most of the work-around plugins they suggested are no longer an option.

Any ideas?

Also, once the problem is fixed.. is there any way for me to obtain the lost email? I use the form for my business site and have undoubtedly lost leads because of this..

WP 3.4.2
CF7 3.3.1

https://www.ads-software.com/extend/plugins/contact-form-7/