Call to undefined method Twocheckout::sandbox()

[shaibal13]

When i try to pass sandbox(true) it gives this and in TwoCheckout there is nofunction named sanbox

[kesato]

i've same problem when i change to test the payment on the sandbox

[domagoj-orioly]

They've changed the way they process demo transactions.

In order to create demo transaction, you can just pass [ ..., 'demo' => true ] property with your transaction request. Read more about it here:
https://knowledgecenter.2checkout.com/API-Integration/Transition_guides/Transition_Guide_for_2Checkout_Sandbox