When you sync your Shipment Tracking information back to Amazon seller central, you are required to send a MerchantFulfillment ID. Acctivate sends the Package ID of the Shipment in this field. The MerchantFulfillmentID is required to be fully numeric by Amazon. Acctivate doesn’t check that your Package ID’s are fully numeric though and so alphanumeric characters are allowed to be sent. This can cause Amazon to not accept the tracking information sent from Acctivate without showing an error in the webstore sync.
If you are sending tracking information back to Amazon in your webstore sync and you are not receiving any errors but the orders are not being updated on the webstore, then you may need to check how your numbers for Package ID’s are configured in Acctivate. To do so, go to File > Configuration Manager > Company > Numbers. Look to the Package ID Prefix and Suffix. If there are alpha values in those fields, you will need to remove them.