A few reasons for the issue that you are encountering while filling the registration form could be the required field that is missing information or a field with information entered in an invalid format. Some Enrollment forms do not accept the same contact number for multiple guardians. Please verify that all the required fields on the form are filled in a valid format.
You could check those fields through the following steps.
Also, I would recommend filling out the form using Google Chrome or Mozilla Firefox browsers as our Enrollment forms work best with these browsers.