Allow Cancelled Orders to Update Status or be Restored via API
If you use cart software with many plugin options some of them will make assumptions that don't jive with ShipStation.
For example, if a payment is declined they can change the order status to Cancelled. ShipStation will import this as a Cancelled order. When the customer tries to pay with another payment method and succeeds their order will remain Cancelled because ShipStation does not allow you to update the status of Cancelled orders via API.
Please change this, it is ridiculous. ShipStation is not supposed to be the one making assumptions about your workflow, that's why it's so customizeable. Except in this one instance.
Don Vida ShipStation - SS2 commented
additional related ticket: https://shipstation.zendesk.com/agent/tickets/466142