Hey @ckas,
Do you have the ReCaptcha features of Community Events enabled? If not, please enable them and see if that helps – you can find these features in Events > Settings > Community in your admin; follow the on-screen directions for activating these Captcha features.
One additional step might be to add and activate the plugin called “Akismet” to your site.
Other than these two solutions, this unfortunately falls outside our control or the control of our plugin; you should take these two steps and then if problems persist you should also contact your web host for further assistance.
Thank you,
George