New User Registration Failing: You did not pass the validation check used to prevent spam submissions

OJS Version: OJS 3.1.2.4
Since yesterday, our users are unable to register on our site and get the " You did not pass the validation check used to prevent spam submissions." message
The only warning in PHP log file is: “Call to deprecated/non-functional Submission::getLocalizedSubject.”
As per the other threads about similar issues, we have double-checked open, captcha keys settings in the PHP config files.

Any ideas on what else we could look for?

test:

nano config.inc.php

Set momentarily:

recaptcha = Off

Can you test if…?

Yes turning the captcha off worked and the user registration worked fine.

Also on the Google recpatcha console we see the following:
We detected that your site is not verifying reCAPTCHA solutions. This is required for the proper use of reCAPTCHA on your site. Please see our developer site for more information.

We have not changed anything and the captcha was working fine earlier:
image

and if you delete this site on recaptcha and create a new site with v2? and copy and paste the new keys?

Thanks.

We are already on v2
image

Did you manage to solve this , having the same issue now .

Thank you