WordPress contact form 7 not sending, SOLVED!

We have been updating customer’s websites to the latest WordPress 5.1.1 and all PlugIns updates. We have removed the Captcha Plugin that used Google Recaptcha v2 as we wished to move a a more secure and faster version of PHP and used the Contact Form 7 integration with reCaptcha v3.

When sending, we failed each time with the response

“There was an error trying to send your message. Please try again later”

We saw the possible solution to check that the wp-footer() was still included in the theme footer.php and this was there as before.

The Contact Form was rechecked and resaved and still it did not work. We then checked the keys, deleted and reapplied to Contact Form 7. It was then that we noticed when adding the domain to the
Google reCAPTCHA Settings Page that we had added it with the “www.” preceding the domain name. We removed this, saved the settings and retested the sending.

It worked and we applied it to all the other V3 settings where appropiate.