I should have said that the my public store URL works when issuing a GET, but fails on a PUT/POST/DELETE - you will get 301 redirected back to a  '999xxx.myshopify.com' URL. To fix the problem, always use '999xxx.myshopify.com' as the domain, and all...

So...newbie error. I was using the external friendly domain name of my store instead of my store name that you can see when logging into the admin (e.g. 'https://admin.shopify.com/store/999xxx) - the '999xxx' part is what you should be using as '999x...

 I'm trying to start using the REST API, so am working in Postman first. I can get products, but I am unable to update a product's title. The PUT appears to work (I get back a 301) but the title never changes in the store. I am sure I am doing someth...