Cannot create reservation for a closed sales order.

Cannot create reservation for a closed sales order.
This Post is about the Error message "Can not create reservation for a closed sales order”, from the error message it is very clear that while Pick release process try to process the Delivery details associated with a line that is either closed or cancelled thus error out the pick release process.
Below is Checklist
Check the Order line for

• Open Flag
• Flow Status Code
• Shipped and Invoice Qty

For a line to be process by Pick Release process

• Open Flag          =Y
• Flow Status Code    = (it should not be CLOSED)
• Shipped and Invoice Qty    = should be NULL

But if

• Open Flag          = Y
• Flow Status Code    = CLOSED/CANCELLED
• Shipped and Invoice Qty    > 0 (For a non Cancelled line) and = 0 for a Cancelled Line and workflow for Order line is completed

then check the following columns in Delivery Detail table

• Released Statue
• Shipped Qty

If released Status <> 'C' (SHIPPED) and  Shipped Qty > 0
and your order line is closed/Shipped then this is pure case of corruption in wsh_delilvery_details table and one good advise is, If your line is Closed and WDD table has oe_interfaced_flag = Y and inv_interfaced_flag = Y (ITS executed successfully)then change the release status = C and Shipped Qty = Shipped_qty (from oe_order_lines_all table).

(Above advise is based on assumption that Goods are physically shipped to customer), BUT if delivery detail is not physically Shipped, but ITS is executed successfully and Invoice is created in Receivables, then a more analysis is required and a details data-fix is required/

And If released Status <> 'C' (SHIPPED) and Shipped Qty = 0
and your Order line is Cancelled then again it is data - corruption and possible suggestion is cancelled the Delivery details.

Hope that healps.