Nearly always one of five things, and the first two cover most of it. Work down the list.
The order is still a draft
Look at the badge at the top of the order. If it says Draft, the order was saved but never placed, so there is nothing to receive against.
Open it and click Save & confirm PO, then try again.
The location box is empty
Quantity and location share a column, so it is easy to type the quantity, move on, and not realise half the line is missing. Both are needed on every line.
Run your eye down the Qty / Location column and check each row has two boxes filled, not one.
The order is already fulfilled
A Fulfilled badge means everything on the order has been received. Compare the Received column against Ordered to see what the system thinks arrived.
If more has physically turned up than you ordered, it cannot go against this order — the order needs increasing first, or the extra needs its own.
There is nowhere to type the lot or serial number
The Tracking column stays quiet until you have entered a quantity and a location. Before that it just reads "Add qty & location first".
Fill those two in and the Add tracking button appears.
The bin you want is not in the list
The location list only offers bins belonging to the warehouse the order was raised against. If yours is missing, the order is probably for a different warehouse — check the Warehouse column on the order.
Still stuck?
Send us these and we can trace it in one go:
the purchase order number
the badge it is showing
the item and quantity you are trying to receive
the message on screen, word for word