ATM_ID is a parameter, but is not defined as a path parameter or in the parameters section.

Parameter definition issue
ATM_ID should clearly be defined as a parameter but is not currently defined correctly as a path parameter or in the parameters section.

"/banks/{BANK_ID}/atms/ATM_ID": { "get": { "tags": ["2_1_0"], "summary": "Get Bank ATM", "security": [{ "directLogin": [] } ], "description": "<p>Returns information about ATM for a single bank specified by BANK_ID and ATM_ID including:</p><ul> <li>Address</li> <li>Geo Location</li> <li>License the data under this endpoint is released under</li></ul><p>Authentication is Optional</p>", "operationId": "2_1_0-getAtm", "parameters": [{ "in": "path", "name": "BANK_ID", "description": "The bank id", "required": true, "type": "string" } ], "responses": { "200": { "description": "Success", "schema": { "$ref": "#/definitions/AtmJson" } }, "400": { "description": "Error", "schema": { "$ref": "#/definitions/ErrorUserNotLoggedIn" } } } } }

Start by locating the API definition containing the /banks/{BANK_ID}/atms/ATM_ID path and reviewing its GET operation. Confirm how path parameters are declared there, then update the definition so ATM_ID is represented consistently with BANK_ID and verify that the path and parameter declarations match.