Chargent can support multiple gateway records simultaneously, and many Chargent customers utilize multiple gateways to keep business units separate or handle transactions in different geographies.
When only one gateway is active (Active checkbox is checked), Chargent uses that gateway for all transactions by default.
However, when more than one gateway is active, the Gateway field needs to be populated in every Chargent Order, otherwise there will be an error.
Many customers want to populate this Gateway field automatically. Because the Gateway field is a lookup field, it cannot be populated via a workflow rule. Use APEX code to update the field, or Use the Process builder to generate APEX code