Send and Wait for Response - Slack not working

[Diego_Rodriguez]

Describe the problem/error/question

Hi guys, I’m trying to use the Send and Wait for Response integration with Slack. However, every time I attempt to send a simple message, I receive the following error: “Slack error response: ‘invalid_blocks’.”

What is the error message (if any)?

{
“errorMessage”: “Slack error response: "invalid_blocks"”,
“errorDetails”: {},
“n8nDetails”: {
“nodeName”: “Send and Wait for Response”,
“nodeType”: “n8n-nodes-base.slack”,
“nodeVersion”: 2.3,
“resource”: “message”,
“operation”: “sendAndWait”,
“time”: “5/8/2025, 9:25:36 AM”,
“n8nVersion”: “1.92.1 (Self Hosted)”,
“binaryDataMode”: “default”,
“stackTrace”: [
“NodeOperationError: Slack error response: "invalid_blocks"”,
" at ExecuteContext.slackApiRequest (/usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Slack/V2/GenericFunctions.js:104:11)“,
" at processTicksAndRejections (node:internal/process/task_queues:95:5)”,
" at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Slack/V2/SlackV2.node.js:333:7)“,
" at WorkflowExecute.runNode (/usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/workflow-execute.js:689:27)”,
" at /usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/workflow-execute.js:923:51",
" at /usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/execution-engine/workflow-execute.js:1259:20"
]
}
}

Share the output returned by the last node

Information on your n8n setup

• n8n version: 1.92.1
• Running n8n via (Docker, npm, n8n cloud, desktop app): DockerPreformatted text

[darrell_tw]

I am not sure why but my version is same as yours.

Maybe you can put this option and see if the same error will happen?

Guessing the approval button somehow become empty block on your end.

[Diego_Rodriguez]

Hi Darrell, thanks for your response.

I tried, but I still get the same error.