The tracking info can be applied to the orders which have order numbers.
It might happen when the order ID is not fetched from AliExpress (this most often happens due to some issues with the AliExpress server not reverting the requested information; another possible reason of the issue is there is no connection between the website and AliExpress for example, if there are some 3rd party extensions in the browser are blocking the connection).
Please use the 'Edit order and tracking ID' link to upload the order ID.
Once the order ID is uploaded and the tracking number is available at AliExpress, the tracking details will be uploaded as well.