ERP Updation Issue-Cannot make new customers sales orders

We are facing one issue in making sales order for new customers .while making so following error is coming Mandatory -Payment Terms.This issue was happening from last week on wards existing customers have no issue only issue is for new customers.we checked in customer template .now there no option for putting the payments terms .previously it was there .because of this our new customers invoice are on hold .pls do the corrections urgently…