If you're attempting to register for an event you have setup and after registration, the page shows: "Invalid Email Entered - Please click the back button and enter a valid email address"
The chances are that the registration form isn't connected to Aevent properly.
Please check these tutorials:
Clickfunnels:
https://help.aevent.com/en/articles/3820192-integrate-aevent-registration-form-with-clickfunnels-form
Groove:
https://help.aevent.com/en/articles/6277923-integrating-groove-funnels-registration-form-page