First, we recommend testing this with the SKU re-indexing form.
If the item is not indexing over with the SKU indexing form, the error message you receive will indicate the reason why.
If it is indexing over the issue in other cases, it is likely that the rate at which you are indexing your items over is not set correctly.
I.e, your indexing queue may be stuck or your indexing process is still in progress.
