When setting up a Conversational Agent in Agent Builder (setting system instructions, model selection, tools, etc.), clicking Save triggers a PATCH request that returns a 500 Internal Server Error. The agent was created successfully, but no configuration changes can be persisted. I get the error “Something went wrong. Please try again later.”
Error from browser console:
Request URL:(PII Removed by Staff)
Response: {error: {code: 500, message: "Internal error encountered.", status: "INTERNAL"}}
What I’ve tried:
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Verified all relevant APIs are enabled (Vertex AI API, Dialogflow API, BigQuery API, Cloud SQL Admin API)
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Toggled Vertex AI API and Dialogflow API off and on
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Checked and modified org policy vertexai.allowedPartnerModelFeatures — changed from “Denied: All” to allow on the project
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Verified IAM service agents exist (Dialogflow Service Agent, Vertex AI Service Agent)
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Confirmed the user has Organization Administrator and project Owner roles
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Tried multiple browsers
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Region is set to us-west1 — no option found in the Agent Builder UI to change the agent’s region after creation
The error is consistent and reproducible across all save attempts. I am out of ideas, as is AI.
Any idea what might be happening here?
Looks like a backend-side failure in Vertex AI Agent Builder, not a misconfiguration on your end. Your troubleshooting already covers most common causes.It’s likely not your fault if:
Error is 500 (not 403/400)
Happens across browsers
Minimal configs also fail
API calls fail too
Open a Support Ticket with:
Project number
Agent ID
Region (us-west1)
Exact failing endpoint
Tell them or mention that:- Consistent 500 INTERNAL error on PATCH for lowcodeAgents - reproducible across configs and browsers. Likely backend validation or regional support issue.
I have exactly the same problem. I tried everything like the other reporter. All the AI help suggestions have been implemented and still cannot get and agent saving. Very frustrating.
Can confirm I have also been experiencing the same issue: 500 PATCH error when trying to update an agent.
I have the same issue, but with Vertex AI Studio Text-to-Speech Export.
- Export button returns 401 error
- Happened today
- Billing active, API enabled, bucket exists, service account has Storage Object Admin
- Cloud Shell TTS works fine
- Project ID:
- Region: us-central1
This seems to be the same backend issue affecting Vertex AI services. Any update from Google would be appreciated.
I’m experiencing the same issue! I noticed this in my API/Service logs. I’ve also tried using two different accounts, but neither of them saved the data.
