[06/22/2022] Contact Form 7 just released version 5.6 which changed the way validation works, this change has broken the validation message for the All-In-One Image CAPTCHA Pro plugin for Contact Form 7. I am working on a fix, unfortunately, the CF7 developer is still writing the documentation for the new validation method. I will push an update as soon as possible. In the meantime, you can either keep your Contact Form 7 on version 5.5 or disable the CAPTCHA plugin until the update has been released.
If you have already updated to version 5.6 you can download version 5.5 and re-install it and disable auto-update. https://downloads.wordpress.org/plugin/contact-form-18.104.22.168.1.zip
I sincerely apologize for this inconvenience.