Authentication Credentials Reset Automatically in Header Auth Configurations in n8n

[Moises-cmyk]

Bug Description

Issue Description:

I am experiencing an issue while working on the beginner course exercise in n8n: Building the Workflow, specifically in Part 1: Getting data from the data warehouse.

The problem occurs when I try to configure the HTTP Request node using Header Auth. After entering the correct api_key value (j[vKYdY68H(:WFb) in the Header Auth credentials, it automatically resets to a placeholder value (__n8n_BLANK_VALUE...) once I save and close the configuration.

This results in an error when testing the workflow:
"Forbidden - perhaps check your credentials? Authorization data is wrong!"

I have verified that the key is correct and entered it multiple times. However, the value consistently resets itself after saving. I also attempted the following steps without success:

1. Creating a new workflow and reconfiguring the HTTP Request node.
2. Using other authentication methods, such as adding the api_key manually in the "Send Headers" section.
3. Encoding special characters in the api_key using percent-encoding.

This issue persists and prevents me from completing the exercise. It seems to be a bug related to how n8n handles sensitive credentials in Header Auth.

Could you please provide assistance or guidance on resolving this? Let me know if you need further details.

To Reproduce

Steps to reproduce the behavior:

1. Start the beginner course exercise in n8n: Building the Workflow, specifically in Part 1: Getting data from the data warehouse.
2. Add an HTTP Request node to the workflow.
3. Configure the node as follows:
   • Method: GET
   • URL: Provide the correct endpoint URL (e.g., https://internal.users.n8n.cloud/webhook/custom-erp?unique_id=5fa2535192afe364e61c9a3e485f75e3).
   • Authentication: Select Generic Credential Type.
   • Generic Auth Type: Set to Header Auth.
4. In the Header Auth configuration:
   • Enter the Header Auth name as api_key.
   • Enter the Header Auth value as j[vKYdY68H(:WFb.
   • Save the credentials.
5. Test the node by clicking Execute Node.
6. Reopen the HTTP Request node configuration.

---

Expected behavior:
The api_key value (j[vKYdY68H(:WFb) should remain unchanged and the request should authenticate successfully.

Actual behavior:

• The api_key value is automatically replaced with __n8n_BLANK_VALUE... after saving and closing the configuration.
• Executing the node results in the error: "Forbidden - perhaps check your credentials? Authorization data is wrong!"

Let me know if you need more details!
<img width="716" alt="Captura de

pantalla 2025-01-14 102626" src="https://github.com/user-attachments/assets/54a227aa-b33c-47df-b6fe-7d9d14f1eba0" />

Expected behavior

The api_key value (j[vKYdY68H(:WFb) should be saved correctly in the Header Auth configuration without being replaced by the placeholder __n8n_BLANK_VALUE.... Upon executing the HTTP Request node, the workflow should authenticate successfully and retrieve data from the endpoint without any authorization errors. This would allow me to proceed with the beginner course exercise without issues.

Operating System

Windows 11

n8n Version

1.72.1 (Self Hosted)

Node.js Version

n8n-nodes-base.httpRequest

Database

SQLite (default)

Execution mode

main (default)

[Joffcom]

Hey @Moises-cmyk,

We have created an internal ticket to look into this which we will be tracking as "N8N-8103"

[Joffcom]

Hey @Moises-cmyk,

This is likely because you have the field set to be an expression, Can you turn this off and enter the credential again and it should be good to go. The value you are seeing is what we return when the expression is viewed to prevent leaking the credentials to users that are viewing it.

[Moises-cmyk]

How do I disable it? I clicked on fx, but it doesn't do anything. I deleted "expression," but nothing changes; the same issue keeps happening. 

[Joffcom]

Hey @Moises-cmyk,

Delete the expression value, Then click the text in the image below, once done input your credential and click save. From this point don't change it back to an expression as you will always see that n8n_blank value if you do.

[Moises-cmyk]

The same error keeps appearing. The password changes itself automatically, as shown there. It keeps resetting itself.
In fact, if I delete the content of the "Value" field and save, the changes are kept. However, when I write something in the field, it doesn’t respect the edit, and the default value appears again.

Is it possible that the Dataset URL: https://internal.users.n8n.cloud/webhook/custom-erp is incorrect?

[Joffcom]

Hey @Moises-cmyk,

Yes that is expected, The length will look bigger as we don't pull the actual credential out of the database instead we return the blank value.

The password itself will still be in your database and unchanged, The error message you are getting is saying the unique ID is incorrect this looks to be because in the node you are using a header value of api_key and not unique_id as the course tells you.

To resolve this in the node set the header name to unique_id and set the value to the ID you got in the email, Add the credential to it that you have saved there and test the node this should then work.

[Moises-cmyk]

Perfect, thank you so so much!!!!!

[Joffcom]

For now I am going to move this to closed, If it is still an issue let me know.

[deemeetree]

This is still an issue. When I try to use your Bearer auth or custom auth with Authentication header, the token is not passed through. Do you have a limitation on the length there maybe?