Amazon will reject ShipStation's shipment notifications if you create too many individual shipping labels in a short period of time. This is known as "throttling." When you visit ShipStation's Shipments tab and search for the order(s) that weren't updated in Amazon Seller Central, you may notice that any associated shopping cart icons are red. If you click on a red shopping cart icon, you'll see a pop-up like the following:
This isn't a ShipStation-specific limitation; any third-party application connecting to your Amazon account is limited in terms of how often it can push or pull information. If that rate limit is exceeded, Amazon will temporarily slow down or cut off the connection between the two. If you're interested in the technical details, check out Amazon's technical documentation.
So if your shipment notifications got throttled by Amazon, there are a few things you can do:
- The easiest thing is to do nothing, since we have an automated process that tries to resubmit the tracking after some time has passed (usually an hour or so).
- If you don't want to wait for the automatic resubmission, you can manually click the green Retry Failed Steps button shown above; however, if you didn't let enough time pass you will only increase the time Amazon throttles your account.
- The best thing to do is to avoid being throttled altogether by shipping orders in batches, rather than individually. For example, creating 50 shipping labels one at a time will push information to Amazon 50 times, but a batch of 50 orders would only notify Amazon once!