When Shuttle marks an Etsy order as shipped, it sends the tracking number from the order's Shopify fulfillment. Some tracking numbers can't be sent to Etsy. When that happens, the order stays open on Etsy and you get an email with the subject "Shuttle couldn't mark an Etsy order as shipped". The email names the Etsy order and shows the tracking number that was refused.
Why was the tracking number refused?
A tracking number is refused when it does any of these things:
It contains a word Etsy does not allow. A common example is a placeholder such as "CustomerPickup" on a local pickup order.
It contains a web address or tracking link instead of the number on its own.
It contains characters other than letters and numbers.
It is shorter than 4 characters.
What happens to an order with a refused tracking number?
Shuttle stops sending an order with a refused tracking number to Etsy, so the same number is not refused again and again. You get one email for each order.
The order stays open on Etsy until you change the tracking number or mark the order shipped on Etsy yourself.
Fix a refused tracking number
You can fix a refused tracking number in either of two ways:
In Shopify, open the order and edit the tracking number on its fulfillment. Enter only the carrier's tracking number, using letters and numbers. Once the number changes, Shuttle tries the order again.
In Etsy, open the order and mark it as shipped yourself.
If the order still isn't marked shipped on Etsy after you change the tracking number, mark it shipped on Etsy.
When the Default tracking code setting was refused
Shuttle uses the Default tracking code setting only when an order's Shopify fulfillment has no tracking number. If the email shows the code from your Default tracking code setting, it's the setting that has to change:
Go to Settings > Orders.
In the Order fulfillment section, change Default tracking code to a valid tracking number or clear it.
Click Save.
Once the code changes, Shuttle tries the affected orders again. If one is still open on Etsy afterwards, mark it shipped on Etsy.