AP invoices not flowing to Asset Management system

Our system is supposed to allow AP invoices to flow through to the asset management system and create an asset automatically. We are coming across an issue where some of these are not flowing through. Nothing shows up on error reports that would give us a clue as to where the invoice is being held up, on our side we can see a variance but we can't figure out why an asset wasn't created for it. What troubleshooting options do we have at this point?