If you want to send shipments to Jersey and other Channel Islands, via Tracked or Signed services, you'll have to make some changes to the order details. Tracked and/or Signed services won't actually work for Jersey and Channel Islands because they're not supported.
What to do?
You need to set the country of the order to UK (in your store/channel), before you ship it and send it to Shiptheory for processing. Royal Mail then will consider it as a domestic shipment and will allow Tracked and/or Signed services to be used.
Still having troubles?
Please feel free to contact Support, and we'll be happy to help.