Upon further investigation, I stumbled across this older post:
http://wordpress.org/support/topic/error-sending-form?replies=5
I followed the last user’s suggestion and my forms are working again. I consider this a stop-gap until a real solution is created.
Having similar issue. I have done nothing with the site in weeks, and all at once the form is giving the “Security check: referal does not match this site.” error. My only guess is that the recent WP update may have caused it? Looking forward to any solutions anyone has.
On a side note, when I submit and get the error, I’m able to hit BACK and submit again and it works. Whatever that’s about…
