You may encounter an issue where your EMV will beep twice when trying to accept AMEX payments, you may or may not have an error message show on the screen of the till when this happens.
If this happens, you will not be able to take AMEX via any method and the customer will need to use a different card.
What Causes This Issue?
This happens when the configuration for AMEX against your devices Terminal ID is either non existent, or misconfigured.
For example, if the currency on your MID is set incorrectly this will occur.
It will also occur if you have not configured AMEX with us on deployment.