Getting this dreaded error. Have the pro version, is there a way to disable it and spam check using some other method (you made it clear you don't like captcha, but many of us use it)?
I can't tell if any of my plugins have caching (none are explicitly set to do that), and the theme I am using appears to be using latest JQUERY (though admittedly the error goes away if I use the WP Default theme). BUT if I do switch to the default theme, it validates and accepts the form entries, there is no error, but no email is sent either (the Entry is accepted but only logged into the database). Likely a second issue.
Struggled with this and the limits on the logic employed for multiple Conditional Fields most of the day (and I am a fair object oriented programmer)... but I am stumped on what to do about the Nonce error as the theme is unlikely to be updated and too complex for me to update.
Any ideas? (Since it is a paid Pro version, I was hoping for a more direct form of support.)