Your client needs to create a PO for a new vendor.

Creating the purchase order: Using Zoho Inventory, selecting "Contacts" reveals a form to create a new company. Once the user has done so, the new company is not available for creating a PO.

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The selection box for "Vendor Name" does not have the new contact in the drop down. This brings the business process to a stop until Zoho synchronizes the contacts.

Solution: Creation of the new contact kicks off a synchronization process immediately.