Seeing the IR001 error message typically means there is an issue with the payment provider integration set up (perhaps an incorrect value entered into a field, etc.)
Payment Provider options can be found in the Setup > Integrations > Payment Provider section of WishList Member.
The IR001 error message is usually caused by something like an incorrectly pasted URL, API Key, etc. (depending on the specific integration settings). A step in the integration process may have been missed or a space or incorrect value may have been copied and pasted during the setup process.
Note: If you are testing with a PayPal Sandbox account, the PayPal Sandbox info needs to be correct as well.
The IR002 error message is usually caused by an Invalid Registration URL (Invalid Payment Provider Integration Thank You URL or an Invalid Simple Registration URL)
If either of these error messages are encountered, it is recommended to check the payment provider integration setup to ensure all settings are configured correctly and all steps have been run through.