FYI @evanjenkins, @shinji251184,
I have worked around the problem using plugin Contact Form 7 Captcha by 247wd and adding the tag [cf7sr-simple-recaptcha] to my contact forms.
Wordpress 4.9.6 with a variety of plugins including Yoast, as you both have.
Best of luck.
Hi @takayukister, I’m having the same problem as the 2 people before.
I have tried your suggestion to @evanjenkins and it has made no difference.
My list of plugins includes Yoast, and W3 Total Cache, among many others, but it still didn’t work after changing theme and disabling all plugins but Contact Form 7 and Contact Form 7 Captcha.
I’ve tried about 3 or 4 alternatives that add reCAPTCHA and all produce the same result.
When I remove the [recaptcha] tag, the form submits immediately.
Thanks