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 the associated shopping cart icons are red.
If you click on a red shopping cart icon, you'll see a pop-up like the following:
The message "Request is throttled" indicates Amazon received more shipment notifications from your account than allowed in a 30-minute period.
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.
If your shipment notifications have been throttled, try the following:
- In the Shipment Status popup, click the green Retry Failed Steps button (as shown above); however, please note that if you didn't let enough time pass (at least 30 minutes since the last notification attempt) you will only increase the time Amazon throttles your account.
- To avoid being throttled altogether, try 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!
- The batch option is only valid for accounts set to notify the marketplace on label creation. If using delayed notifications, ShipStation will still send each marketplace notification individually instead of as a batch.
- If you continue to have trouble with notifications not going through to Amazon, please contact ShipStation support for further assistance.