The fulfilment location in Shopify is mandatory. When you fulfil your orders in Shopify, you must specify the location where orders will be fulfilled. 

For example, if you have two shops in different cities (ie Melbourne and Perth), you will need to specify if the order will be fulfilled in Melbourne or Perth. You also need to be sure that the selected location has the stock.

If you don't define a location in your settings, the first location will be used to fulfil your orders. However, this location might not have the required stock to fulfil your order. The order will not be updated in Shopify and a write-back error is displayed.

To resolve this you must follow the steps below to specify the fulfilment location:

1. Go to Settings, then select Integrations.
2. Click Shopify Settings.
3. Click Lookup, and select the location you want to use.
4. Click Save.

Deactivate email notifications

Deactivate email notifications, so customers won't be notified by an email from Shopify when an order is created or updated.

1. Go to Settings, then select Integrations.
2. Select Shopify Settings.
3. Select Disable Shopify customer notification.
4. Click Save.

Unable to activate checkout rates

When activating checkout rates for Shopify you receive the following error:

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

This typically means the Shopify subscription is on the Basic Plan or the Third-party calculated shipping rates add-on is not active. 

For live rates at checkout on Shopify its necessary to have their Advanced Plan or to have the third-party carrier-calculated shipping rates add-on. 

Shopify Article | Third-party calculated shipping rates