When patrons are submitting requests, there are two parts for setting up the required fields.
If you have a field that is in the WebValidation table, but not on the Web page, then the patron will not be able to submit the request because the Web Validation table will require the field and the patron cannot update the field. So you will need to delete the Web Validation field or do not require the field anymore in the WebValidation table. More information about this is found in the Changing Required Fields - ILLiad documentation.