What is the term used for a response to an acquirer's authorization request that requires the merchant to contact the issuer directly?

The term used for a response to an acquirer's authorization request that requires the merchant to contact the issuer directly is known as "Call-Me." This response indicates that the issuer needs to provide additional information or verification, which cannot be completed through the usual automated channels.

In practice, when a merchant receives a "Call-Me" response, they are instructed to reach out to the cardholder's issuing bank directly to gain further insights into why the authorization could not be processed automatically. This situation often arises from various factors such as potential fraud alerts, transaction questions, or limits being reached.

Understanding this term is essential for professionals in the electronic transaction space, as it highlights the importance of direct communication between merchants and issuers in ensuring transaction integrity and customer service.