UPDATE: This should now be resolved. If you are still having trouble and you have already cleared your browser's cache and cookies (the help article below has instructions) are still unable to ship please reach out to our support team.
We are currently receiving multiple reports of errors associated with Stamps. We have reached out tohttp://Stamps.com, and they are aware of the issue and working to resolve it as soon as possible. ShipStation Status Page:https://status.shipstation.com
Currently, labels and rating using Stamps and UPS from ShipStation services are currently disabled at this time while this is being resolved. We will make sure to keep you updated when this is turned back on.