The remote server returned an error: (422) Unprocessable Entity.

Hello

I am new to shopify and API’s. i am trying to update a fulfillment, looking at the document, running the open.json, it changes the status to In_Process, i am receiving The remote server returned an error: (422) Unprocessable Entity.

https://XXXXXXX.myshopify.com/admin/api/2022-10/fulfillment_orders/5223589642533/open.json

i have tried a PUT and POST, both return error’s

Any suggestions would be appreciated

Regards

John