Dynamics 365 WebApi - BATCH request - Error - The message header ' ' is invalid

Question

Anyone is facing the follow error message, trying to execute a BATCH request for Dynamics 365 WebApi? I'm using Postman.

{
    "Message": "The message header '  ' is invalid. The header value must be of the format '<header name>: <header value>'.",
    "ExceptionMessage": "The message header '  ' is invalid. The header value must be of the format '<header name>: <header value>'.",
    "ExceptionType": "Microsoft.OData.ODataException",
    "StackTrace": "   at Microsoft.OData.MultipartMixed.ODataMultipartMixedBatchReaderStream.ValidateHeaderLine(String headerLine, String& headerName, String& headerValue)\r\n   at Microsoft.OData.MultipartMixed.ODataMultipartMixedBatchReaderStream.ReadHeaders()\r\n   at Microsoft.OData.MultipartMixed.ODataMultipartMixedBatchReaderStream.ProcessPartHeader(String& contentId)\r\n   at Microsoft.OData.MultipartMixed.ODataMultipartMixedBatchReader.SkipToNextPartAndReadHeaders()\r\n   at Microsoft.OData.ODataBatchReader.ReadImplementation()\r\n   at Microsoft.OData.ODataBatchReader.InterceptException[T](Func`1 action)\r\n   at Microsoft.Crm.Extensibility.OData.CrmODataBatchHandler.<ParseBatchRequestsAsyncImplementationAsync>d__16.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Crm.Extensibility.OData.CrmODataBatchHandler.<>c__DisplayClass9_0.<<ParseBatchRequestsAsync>b__0>d.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.PowerApps.CoreFramework.ActivityLoggerExtensions.<ExecuteAsync>d__11`1.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Xrm.Telemetry.XrmTelemetryExtensions.<ExecuteAsync>d__6`1.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Crm.Extensibility.OData.CrmODataBatchHandler.<ParseBatchRequestsAsync>d__9.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Web.OData.Batch.DefaultODataBatchHandler.<ProcessBatchAsync>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Web.Http.Batch.HttpBatchHandler.<SendAsync>d__0.MoveNext()",
    "ErrorCode": "0x0"
}

---

Image of Postman headers

Here's my Body Content:

--batch_AAA123

Content-Type: multipart/mixed;boundary=changeset_BBB456


--changeset_BBB456

Content-Type: application/http
Content-Transfer-Encoding:binary
Content-ID: 1

POST https://copasa.crm2.dynamics.com/api/data/v9.1/tasks HTTP/1.1
Content-Type: application/json;type=entry
Accept: application/json

{"subject":"Task 1 in batch","[email protected]":"https://copasa.crm2.dynamics.com/api/data/v9.1/accounts(1AD045E1-7DE4-E911-A812-000D3AC058C3)"}

--changeset_BBB456

Content-Type: application/http
Content-Transfer-Encoding:binary
Content-ID: 2

POST https://copasa.crm2.dynamics.com/api/data/v9.1/tasks HTTP/1.1
Content-Type: application/json;type=entry
Accept: application/json

{"subject":"Task 2 in batch","[email protected]":"https://copasa.crm2.dynamics.com/api/data/v9.1/accounts(1AD045E1-7DE4-E911-A812-000D3AC058C3)"}

--changeset_BBB456--

--batch_AAA123

Content-Type: application/http
Content-Transfer-Encoding:binary

GET https://copasa.crm2.dynamics.com/api/data/v9.1/accounts(1AD045E1-7DE4-E911-A812-000D3AC058C3)/Account_Tasks?$select=subject HTTP/1.1
Accept: application/json


--batch_AAA123--

Answer 1

Nothing looks wrong except the extra white lines between Batch request unique identifier & headers, the error maybe coming because of that. Remove the extra white lines like below:

--batch_AAA123
Content-Type: multipart/mixed;boundary=changeset_BBB456

--changeset_BBB456
Content-Type: application/http
Content-Transfer-Encoding:binary
Content-ID: 1

POST https://copasa.crm2.dynamics.com/api/data/v9.1/tasks HTTP/1.1
Content-Type: application/json;type=entry
Accept: application/json

{"subject":"Task 1 in batch","[email protected]":"https://copasa.crm2.dynamics.com/api/data/v9.1/accounts(1AD045E1-7DE4-E911-A812-000D3AC058C3)"}

--changeset_BBB456
Content-Type: application/http
Content-Transfer-Encoding:binary
Content-ID: 2

POST https://copasa.crm2.dynamics.com/api/data/v9.1/tasks HTTP/1.1
Content-Type: application/json;type=entry
Accept: application/json

{"subject":"Task 2 in batch","[email protected]":"https://copasa.crm2.dynamics.com/api/data/v9.1/accounts(1AD045E1-7DE4-E911-A812-000D3AC058C3)"}

--changeset_BBB456--

--batch_AAA123
Content-Type: application/http
Content-Transfer-Encoding:binary

GET https://copasa.crm2.dynamics.com/api/data/v9.1/accounts(1AD045E1-7DE4-E911-A812-000D3AC058C3)/Account_Tasks?$select=subject HTTP/1.1
Accept: application/json

--batch_AAA123--