Error on Outlook node/Create Draft when adding and attachment

Questions
1

Describe the problem/error/question

When using Outlook

This issues was already mentioned in the following post but it was closed without confirming if the issue was solved.

I confirm that in version 1.88.0 of n8n it’s still happening.

If you create an Outlook Node/Create Draft and add an additional field attachement. You will get the following error. I provide and example workflow bellow

What is the error message (if any)?

{
  "errorMessage": "were unable to deserialize ",
  "errorDetails": {
    "rawErrorMessage": [
      "400 - {\"error\":{\"code\":\"UnableToDeserializePostBody\",\"message\":\"were unable to deserialize \"}}"
    ],
    "httpCode": "400"
  },
  "n8nDetails": {
    "nodeName": "Microsoft Outlook1",
    "nodeType": "n8n-nodes-base.microsoftOutlook",
    "nodeVersion": 2,
    "resource": "messageAttachment",
    "operation": "add",
    "itemIndex": 0,
    "time": "4/15/2025, 2:17:21 PM",
    "n8nVersion": "1.88.0 (Cloud)",
    "binaryDataMode": "filesystem",
    "stackTrace": [
      "NodeApiError: were unable to deserialize ",
      "    at ExecuteContext.requestWithAuthentication (/usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/node-execution-context/utils/request-helper-functions.js:991:19)",
      "    at processTicksAndRejections (node:internal/process/task_queues:95:5)",
      "    at ExecuteContext.requestWithAuthentication (/usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/node-execution-context/utils/request-helper-functions.js:1147:20)",
      "    at ExecuteContext.microsoftApiRequest (/usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Microsoft/Outlook/v2/transport/index.js:52:12)",
      "    at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Microsoft/Outlook/v2/actions/messageAttachment/add.operation.js:133:20)",
      "    at ExecuteContext.router (/usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Microsoft/Outlook/v2/actions/router.js:85:26)",
      "    at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Microsoft/Outlook/v2/MicrosoftOutlookV2.node.js:38:12)",
      "    at WorkflowExecute.runNode (/usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/workflow-execute.js:681:27)",
      "    at /usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/workflow-execute.js:915:51",
      "    at /usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/workflow-execute.js:1246:20"
    ]
  }
}

Please share your workflow

Share the output returned by the last node

Information on your n8n setup

  • n8n version: 1.88.0
  • Database (default: SQLite): N/A
  • n8n EXECUTIONS_PROCESS setting (default: own, main):
  • Running n8n via (Docker, npm, n8n cloud, desktop app): n8n cloud
  • Operating system: N/A
2

Any updates?