There are a few reasons why you might face issues installing Zip on your Shopify store.
Below are a few things you may need to check are in order before installing the Zip Payments App.
Your store currency must match the Zip gateway region
To install Zip correctly your default store currency must match the region of the Zip Payment App that you are trying to install
For example, if you are an Australian business selling in Australian dollars, you must be installing the AU Zip Payment Gateway and have your default currency set to AUD.
Your store address must match the Zip gateway region
To install Zip correctly your default store address must match the region of the Zip Payment App that you are trying to install
For example, if you are an Australian business selling in Australia, you must be installing the AU Zip Payment Gateway and have your default currency set to a valid Australian address.
You must be using the correct API keys
If you are experiencing issues what inputting your API keys to the Zip settings page, you must ensure that you are inputting the API keys that match the environment that has been selected.
As shown below you can see "Production" mode has been selected. This means you must be using your production (live) API keys from the live Zip Merchant Dashboard
The same applies when "Sandbox" has been selected, you must be using your sandbox (test) API keys from the Demo Zip Merchant Dashboard.