Failed to get the plug-in implementation, check the plug-in configuration for payment system name ThePluginName and payment configuration ID default.

This FoundationApplicationException will be thrown when you add a new payment plugin in, but have an issue with the PluginDeployment.xml file.

First, check you have a folder for the plugin:
WC/xml/config/payments/ppc/plugins/ThePluginNamePlugin

Second, verify there is a PluginDeployment.xml file located in that folder.

Third, the most likely issue, verify the PluginInformation line.

<PluginInformation
		jndi="ejb/com/company/payment/plugin/ThePluginNameHome"
		home="com.company.payment.plugin.ThePluginNameHome"
		name="ThePluginNamePlguin" version="1.0.0" vendor="You"
		independentCredit="true" virtualTerminal="none">

The jndi and home attributes need to be set according to your payment plugin. If you have the source, you can verify the correct values in the ibm-ejb-jar-bnd.xml file of the plugin project. There will be a jndiName that shows the correct path to the Home interface.

Name is the name of the plugin. The name shown in the error message, in this case ThePluginName, is not necessarily the name that needs to be used. Use the error message name in the PaymentSystemPluginMapping.xml file to have the PaymentSystemName that matches it. That element would contain a Mapping element, and the pluginName attribute of that element is the name that should be used.

After updating the file to use the correct information, restart the server, and the error should be gone.