What does 'Invalid shipment.ID' mean as a response from SendCloud?

An 'Invalid shipment.ID' notification often occurs when the chosen carrier from SendCloud is not suitable for the specified delivery address. This can happen, for example, when sending an address with an incorrect postal code, due to a spelling or formatting error. SendCloud also checks if postal codes belong to a country. For example, in Belgium, postal codes are typically 4 or 5 digits long, and an NL postal code with 'Belgium' as the country will also result in rejection like this.

Unfortunately, SendCloud does not provide any explanation for the rejection of a carrier. It is currently unknown if the websites provide more information. There have been situations where the shipment was visible as rejected within SendCloud, but for some reason, that is not always the case. In any case, it is advisable to check the delivery address in combination with the chosen carrier.