The problem is in the code – plugin isn’t being updated and recaptcha isn’t working. Try this:
Following up…I decided not to wait or try the various “fixes” posted on other threads and forums.
I ended up deleting Contactform 7 from all of the sites I manage and installed the free version of WPForms:
https://wpforms.com
WPForms can still utilize reCaptcha v2, both “Checkbox” and “Invisible”.
The free version of WPForms is still pretty robust and the resulting email messages are much nicer.
I’ve tried WPForms in several configurations and all have worked flawlessly so far. They even offer info for some “hacks” like adding the sender’s IP address, etc.:
https://wpforms.com/web-form-hacks-to-unlock-customer-data/
I’ll post back if there are any issues or if the clients start receiving spam, but so far so good.