sharlene_c on "[Plugin: Contact Form 7] CAPTCHA suddenly no longer working"

I have 2 forms on my site. One is still working fine but the other all of a sudden no longer has the captcha showing and when I submit the form the fields remain populated instead of clearing. Does anyone have any idea why this would be so?
Thanking you in advance for any help.

https://wordpress.org/plugins/contact-form-7/