If you’re getting the error below when you or users submit a form, It means that there is another plugin (social share, third party data submitters etc.) or your theme on your site, messing up the integrity of your session.
There was a problem with your submission! Possible causes may be that the submission has taken too long, or it represents a duplicate request.
All of the forms of used by our plugins are protected against spam and various types of attacks automatically. Third party plugins or themes usually trigger this issue by resetting and changing the session id after it is created by our plugins. If our plugin form code detects that the session id is modified or not the same, it may trigger the protection thinking that non-human user(robot) is trying to submit form data.
If you are using another protection method, you can disable, Cross Site Request Forgery protection per form by:
Plugin Settings > Form > select the form you want to disable> Find CSRF Check field and uncheck > Save
This will disable the protection for the form selected. The recommended approach is to the find what's causing the issue and fix it. You can find what's causing the issue by deactivating the plugins one by one or simply changing your theme and try again.