If you receive the error:
HTTP Status Code 401. The consumer isn’t authorized to access resourceswhen trying to add your Magento 2 Integration to XPS Ship, this can be resolved by editing your Access Token setting in Magento 2 with the steps below:
Log in to your Magento 2 admin panel. On the left-hand side, click on Stores > Configuration
Then under “Services” select “OAuth”.
Next, for “Allow OAuth Access Tokens to be used as standalone Bearer Tokens” select “Yes” from drop-down menu.
Select “Save Config” in the top right corner.
Next, return to the Magento 2 Settings page in XPS Ship, refresh the page, and it should now show the integration is connected.