Please ensure that your API keys and Merchant IDs or Client Secret IDs are all entered correctly. It is best to copy and paste this information directly from the Zip Merchant Portal under Add Zip as a payment option.
If you are using Shopify, please ensure that the test mode is disabled. At this time, it is not possible to test the gateway in this mode. You will need to complete a real order and later on, you may refund it from your platform.
If you are using WooCommerce, another plugin might be conflicting with the Zip checkout. Remove any conflicting plugins first before continuing.
Please email our Merchant Experience team at firstname.lastname@example.org or reach out to your account manager.