Plugin: Visual Form Builder Issue: spambot message with only one form

Hi,
I have a problem with Visual Form Builder. I created six different forms with this plugin and all work well on the site except one. Once the user fills it out and submits it, the plugin returns the message “Hello, spambot!” and the form is not submitted.

Since all the other forms created with the same plugin seem to work correctly I don’t think there’s a conflict with the theme or other plugins (although I also installed Ultimate Member and I heard that some people experienced conflict problems) or any issue connected to the anti-spam filter.

Can the problem derive from specific parameters in the wp settings/discussion?

Thanks in advance for your help!