Mandatory information about my setup:

Have I searched the tickets before posting? YES
Have I searched the forum before posting? YES
Have I read the documentation before posting (which pages?)? YES
Joomla! version: (unknown)
PHP version: (unknown)
MySQL version: (unknown)
Matukio version: (unknown)
Direct link to the page that shows the issue: http://www.rentschpartner.ch/us-litigation-desk/vorabend-seminar


Description of my issue:
Dear Yves
The captcha plugin is not shown in the booking form. Therefore an error message results:
Nachricht

"Ihre Buchung war nicht erfolgreich! Der eingegebene Sicherheitscode (Captcha) ist falsch.incorrect-captcha-sol"

Do you know this problem?
Regards, Louis