I’m creating a chatbot to use on a website. It used to work correctly, answering questions, etc. But suddenly it stopped working and I get the following message:
Hi @Sofesqivo
the workflow might be not published and the PG Vector credentials are empty !
try to fix in this order:
Open Workflow Settings and confirm Execution Logic is set to v1
Reconnect the Postgres credentials on the PGVector Store node
Hit Publish and test via the production chat URL, not “Execute workflow”
Let me know 
Hey, can you share the actual error message text? i cant see the screenshots. Also what n8n version are you on and are you running it via Docker or npm? If you can paste your workflow JSON taht would help a lot too.
Hi @Sofesqivo Welcome! I have personally faced this error and then i have updated my n8n instance and it worked correctly so just upgrade your current n8n instance to the latest stable version.
Yes, of course.
No prompt specified
Expected to find the prompt in an input field called ‘chatInput’ (this is what the chat trigger node node outputs). To use something else, change the ‘Prompt’ parameter
Error details
Node type
@n8n/n8n-nodes-langchain.agent
Node version
3.1 (Latest)
n8n version
2.10.2 (Self Hosted)
Time
12/3/2026, 8:46:19
Stack trace
NodeOperationError: No prompt specified at getPromptInputByType (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_3f8a51621cafcf583d9248e2e2767e62/node_modules/@n8n/n8n-nodes-langchain/utils/helpers.ts:38:10) at prepareItemContext (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_3f8a51621cafcf583d9248e2e2767e62/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V3/helpers/prepareItemContext.ts:47:36) at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_3f8a51621cafcf583d9248e2e2767e62/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V3/helpers/executeBatch.ts:78:47 at Array.map (<anonymous>) at executeBatch (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_3f8a51621cafcf583d9248e2e2767e62/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V3/helpers/executeBatch.ts:73:30) at ExecuteContext.toolsAgentExecute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_3f8a51621cafcf583d9248e2e2767e62/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/agents/ToolsAgent/V3/execute.ts:46:84) at ExecuteContext.execute (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/@n8n+n8n-nodes-langchain@file+packages+@n8n+nodes-langchain_3f8a51621cafcf583d9248e2e2767e62/node_modules/@n8n/n8n-nodes-langchain/nodes/agents/Agent/V3/AgentV3.node.ts:151:10) at WorkflowExecute.executeNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+exporter-trace-otlp_9f358c3eeaef0d2736f54ac9757ada43/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1043:8) at WorkflowExecute.runNode (/usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+exporter-trace-otlp_9f358c3eeaef0d2736f54ac9757ada43/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1222:11) at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+exporter-trace-otlp_9f358c3eeaef0d2736f54ac9757ada43/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:1665:27 at /usr/local/lib/node_modules/n8n/node_modules/.pnpm/n8n-core@file+packages+core_@opentelemetry+api@1.9.0_@opentelemetry+exporter-trace-otlp_9f358c3eeaef0d2736f54ac9757ada43/node_modules/n8n-core/src/execution-engine/workflow-execute.ts:2308:11
I supposedly have it updated, but what I see is that what I send through the chat never reaches the AI agent or arrives as null or empty.
Thanks to checking the PostgreSQL settings as you suggested, I noticed an error in the n8n container; it was due to a missing section when creating it. Thank you very much!