It seems like you are trying to create an E-way bill for the customer who is SEZ registered.
It is not possible to create E-way bill for those SEZ registered customer by creating an normal tax invoice.
We request you to please create an SEZ invoice to create an E-way bill for SEZ registered customer.
Please refer to the below article to create an SEZ invoice.
Please select SEZ with/without IGST payment as a export type to create an SEZ invoice.