When processing orders you might come across the "Failed to generate label: shipment.References.Code:Code is required. 'id' cannot be null" error.
This error is shown when you have references that you are using but are empty.
This could be solved in two ways:
Feel free to follow the step-by-step guide written below or the video guide, as you prefer:
To do so:
1. Find the order through any of the possible ways (after Import Orders, Batches, Order History, etc) as it applies to the case
2. Click the edit button of the order you wish to change
3. Correct the empty reference with the value that applies to the case
4. Press Save to apply the changes
If the rest of the information in the order is correct, you will be able to process it.