If you are struggling to login or have forgotten your password, simply go to the login page of your event: xxx.online-event.co (where xxx is replaced by the name of your event).
Click on the Forgotten/Not received your password? option to reset your password. You will receive an email within 15 minutes with a link to set up a new password.
Once you have done that, you will be able to login.
If you are still having issues with logging in, please speak to your event organiser. Their contact details are usually mentioned in your registration confirmation email.