Checkout error: security code does not match

[karid]

Hi guys. Will you help.me please. When customer trying to order as guest or by creating an acc the error is showing as on attached picture. Not sure whats wrong

[JBW]

Are you using any captcha or spam prevention module? This might insert any security code causing this issue

[karid]

that was the problem. but I still dont understand why if module is on for both : contact form and registration form customers who want to purchase as guest cant place an order as is showing error and not showing captcha box with symbols o put in