delivery block Z3 automatically coming in delivery

Hi All

Please suggest me on the below issue,

Scenario:Sales order is created then the sales document is blocked for credit check.After releasing the document delivery document is created.After saving the delivery document automatically delivery block is coming in delivery header adminisatration data that is Z3-Confirm Price.

But we are not entering any delivery block any where.This delivery block is coming automatically in delivery.This block is coming for a particular customer,But there is no blocking for that customer in VD 05.Is there any other setting for blocking particular customer.

Please revert back with some solution.

Thank you

Goutam