Troubleshooting: Google Document AI CREDENTIALS_MISSING / invalid_scope with HTTP Request Node

Hello callin.io Community,

I'm encountering an issue trying to connect to the Google Document AI API via the HTTP Request node and am stuck in an authentication loop. Any assistance would be greatly appreciated.

My Setup:

• callin.io Version: 1.98.2 (Cloud)
• Objective: To call the Document AI :process endpoint.
• Credential Type Utilized: Google Service Account API

Verified on Google Cloud:

• The Document AI API is enabled.
• A Billing Account is active and properly linked to the project.
• A Service Account exists with the Document AI Administrator role.
• A JSON key for this service account has been generated, downloaded, and is active.

The Problem within callin.io:
I've set up a Google Service Account API credential, successfully pasting the client_email and private_key from the JSON file.

Within my HTTP Request node, I'm using this credential. The remainder of the node's configuration (URL, Body, etc.) is set up correctly. However, I'm facing a catch-22 depending on a specific switch within the credential's settings:

• Scenario 1: With the credential’s Set up for use in HTTP Request node switch set to OFF, the API call fails with a 401 - CREDENTIALS_MISSING error.

• Scenario 2: When the credential’s Set up for use in HTTP Request node switch is toggled ON, the API call fails with a 400 - invalid_scope error.

I've spent considerable time debugging this and have double-checked all configurations on the Google Cloud side. It appears to be a potential bug or an interaction issue between this credential type and the HTTP Request node in the current callin.io version.

Could anyone offer a solution or a workaround? Thank you kindly.