Hi all,
We have enabled Agentforce in our sandbox environment. When attempting to preview a prompt template, we encounter the following error:
“An error occurred during generation. Prompt Engine API failed - Status 404, Response.”
This issue does not occur with the standard templates provided within the org. However, when we create a new prompt template—or copy the instructions from a standard template into a new custom template—we consistently see this error.
When previewing the default standard templates, the response is generated successfully, and we can also see the token usage details.
Has anyone encountered this issue or have insights into what might be causing it?
Hi Jagadeesh!
Since the standard prompt templates work but both newly created and copied custom templates return “Prompt Engine API failed - Status 404”, I’d first check the configuration around the custom prompt template rather than the prompt instructions themselves.
A few things worth verifying:
- Confirm the custom template is using the correct template type and model/provider configuration.
- Check that all referenced resources, merge fields, and grounding sources are available in the sandbox.
- Compare the custom template’s configuration with a working standard template, not just the instructions.
- Verify the required Prompt Builder/Einstein permissions and feature permissions for the user.
- Try creating a very simple custom template with no additional grounding or complex resources and test the preview.
Because the standard templates successfully call the Prompt Engine, a consistent 404 on only custom templates could indicate a sandbox feature/provisioning or backend configuration issue rather than an invalid prompt.
If the simple custom template also returns 404, I’d capture the template configuration and the exact timestamp/request details and raise it with Salesforce Support so they can check the Prompt Engine logs for the sandbox.
