The error message The requested resource could not be found indicates you're attempting to access a record that doesn't exist, or doesn't exist in the current environment.
Check your API keys
A common cause is where you're using a Card token created in the Test environment to try to create a Charge in the Live environment. This can happen when you haven't updated your Publishable and/or Live API Key when switching between the Test and Live environments.
This also applies when using any of the other API resources.