diff --git a/code/Test_definitions/simple-edge-discovery.feature b/code/Test_definitions/simple-edge-discovery.feature
index de75343..b552447 100644
--- a/code/Test_definitions/simple-edge-discovery.feature
+++ b/code/Test_definitions/simple-edge-discovery.feature
@@ -30,39 +30,161 @@ Feature: CAMARA Simple Edge Discovery API, vwip - Operation readClosestEdgeCloud
     And the 200Success object includes the EdgeCloudZone object defined at "#/components/schemas/EdgeCloudZone"
     And the 200Success object includes the optional DeviceResponseBody object defined at "DeviceResponseBody"
 
-  @simple_edge_discovery_error_scenario_01_device_cannot_be_identified
+  @simple_edge_discovery_error_scenario_01_404_device_cannot_be_identified
   Scenario: Error because the device cannot be identified
     Given the request "readClosestEdgeCloudZone" is sent
     When the provided identifier(s) cannot be matched to a device
-    Then Response code is 404 IDENTIFIER_NOT_FOUND
+    Then the response status code is 422
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "IDENTIFIER_NOT_FOUND"
+    And the response property "$.message" contains a user friendly text
 
-  @simple_edge_discovery_error_scenario_02_identifiers_not_supported
+  @simple_edge_discovery_error_scenario_02_422_identifiers_not_supported
   Scenario: Error because the provided identifiers cannot be supported
     Given the request "readClosestEdgeCloudZone" is sent
     When the identifier(s) provided are not supported by the implementation
-    Then Response code is 422 UNSUPPORTED_IDENTIFIER
+    Then the response status code is 422
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "UNSUPPORTED_IDENTIFIER"
+    And the response property "$.message" contains a user friendly text
 
-  @simple_edge_discovery_error_scenario_03_missing_identifier
+  @simple_edge_discovery_error_scenario_03_422_missing_identifier
   Scenario: Error because no identifier was provided
     Given the request "readClosestEdgeCloudZone" is sent
     When No identifier(s) are provided and cannot be derived from any 3-legged access token
-    Then Response code is 422 MISSING_IDENTIFIER
+    Then the response status code is 422
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "MISSING_IDENTIFIER"
+    And the response property "$.message" contains a user friendly text
 
-  @simple_edge_discovery_error_scenario_04_invalid_access_token_context
+  @simple_edge_discovery_error_scenario_04_403_invalid_access_token_context
   Scenario: Error because access token context is invalid
     Given the request "readClosestEdgeCloudZone" is sent
     When the device identifiers are not consistent with access token
-    Then Response code is 403 INVALID_TOKEN_CONTEXT
+    Then the response status code is 403
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "INVALID_TOKEN_CONTEXT"
+    And the response property "$.message" contains a user friendly text
 
-  @simple_edge_discovery_error_scenario_05_service_not_applicable
+  @simple_edge_discovery_error_scenario_05_422_service_not_applicable
   Scenario: Error because the device is not connected to an edge-supporting network
     Given the request "readClosestEdgeCloudZone" is sent
     When the identified device is not connected to an edge-supporting network
-    Then Response code is 422 SERVICE_NOT_APPLICABLE
+    Then the response status code is 422
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "SERVICE_NOT_APPLICABLE"
+    And the response property "$.message" contains a user friendly text
 
-  @simple_edge_discovery_error_scenario_06_operator_cannot_resolve
-  Scenario: Internal error at operator
-    Given the request "readClosestEdgeCloudZone" is sent
-    And the device has been successfully identified
-    When the operator is unable to resolve due to internal error
-    Then the response code is 500 INTERNAL
+# Generic 400 errors
+
+  @simple_edge_discovery_error_scenario_06_400_bad_request
+  Scenario: Invalid Argument. Generic Syntax Exception
+    Given the request body is set to any value which is not compliant with the schema at "/components/schemas/RequestBody"
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 400
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "INVALID_ARGUMENT"
+    And the response property "$.message" contains a user friendly text
+
+  @simple_edge_discovery_error_scenario_07_400_no_request_body
+  Scenario: Missing request body
+    Given the request body is not included
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 400
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "INVALID_ARGUMENT"
+    And the response property "$.message" contains a user friendly text
+
+  @simple_edge_discovery_error_scenario_08_400_device_empty
+  Scenario: The device value is an empty object
+    Given the request body property "$.device" is set to: {}
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 400
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "INVALID_ARGUMENT"
+    And the response property "$.message" contains a user friendly text
+
+  @simple_edge_discovery_error_scenario_09_400_device_identifiers_not_schema_compliant
+  # Test every type of identifier even if not supported by the implementation
+  # Note that device schema validation errors (if any) should be thrown even if a 3-legged access token is being used
+  Scenario Outline: Some device identifier value does not comply with the schema
+    Given the request body property "<device_identifier>" does not comply with the OAS schema at "<oas_spec_schema>"
+    And a 2-legged or 3-legged access token is being used
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 400
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "INVALID_ARGUMENT"
+    And the response property "$.message" contains a user friendly text
+
+    Examples:
+      | device_identifier                | oas_spec_schema                             |
+      | $.device.phoneNumber             | /components/schemas/PhoneNumber             |
+      | $.device.ipv4Address             | /components/schemas/DeviceIpv4Addr          |
+      | $.device.ipv6Address             | /components/schemas/DeviceIpv6Address       |
+      | $.device.networkAccessIdentifier | /components/schemas/NetworkAccessIdentifier |
+
+  # The maximum is considered in the schema so a generic schema validator may fail and generate a 400 INVALID_ARGUMENT without further distinction, and both could be accepted
+  @simple_edge_discovery_error_scenario_10_400_out_of_range_port
+  Scenario: Out of range port
+    Given the request body property  "$.device.ipv4Address.publicPort" is set to a value not between 0 and 65535
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 400
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 400
+    And the response property "$.code" is "OUT_OF_RANGE" or "INVALID_ARGUMENT"
+    And the response property "$.message" contains a user friendly text
+
+  # Generic 401 errors
+
+  @simple_edge_discovery_error_scenario_11_401_no_authorization_header
+  Scenario: No Authorization header
+    Given the header "Authorization" is removed
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 401
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 401
+    And the response property "$.code" is "UNAUTHENTICATED"
+    And the response property "$.message" contains a user friendly text
+
+  # In this case both codes could make sense depending on whether the access token can be refreshed or not
+  @simple_edge_discovery_error_scenario_12_401_expired_access_token
+  Scenario: Expired access token
+    Given the header "Authorization" is set to an expired access token
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 401
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 401
+    And the response property "$.code" is "UNAUTHENTICATED"
+    And the response property "$.message" contains a user friendly text
+
+  @simple_edge_discovery_error_scenario_13_401_invalid_access_token
+  Scenario: Invalid access token
+    Given the header "Authorization" is set to an invalid access token
+    When the request "readClosestEdgeCloudZone" is sent
+    Then the response status code is 401
+    And the response header "x-correlator" has same value as the request header "x-correlator"
+    And the response header "Content-Type" is "application/json"
+    And the response property "$.status" is 401
+    And the response property "$.code" is "UNAUTHENTICATED"
+    And the response property "$.message" contains a user friendly text