Unable to add Revolut Business API credentials

[Nejc]

I am Encountering unauthorized_client Error During Revolut API OAuth2 Integration in n8n

I’m attempting to integrate the Revolut API with n8n to automate transaction retrieval. Despite following the available Revolut documentation, I consistently encounter the following error during the OAuth2 authorization process:

Describe the problem/error/question

I can successfully manually obtain the access and refresh tokens via my CLI.
But when I want to add new Oauth2 API credentials and authorize through that. The authorization page successfully opens up and I believe I even receive the correct code via the url, but the page displays the following error, and the integration remains “un-connected”

Error: The client is not authorized to request an authorization code using this method.
More details
{"error":"unauthorized_client","error_description":"Failed to authorise client"}
Failed to connect.

I am pretty sure i am missing something, but i am not sure what…

here is my credentials setup:

• I used the OAuth Redirect URL provided by N8N for JWT generation
• auth url is the same as you would click in the Revolut page → Enable access / written in docs
• access token URL is the same as in docs
• client secret is my client_assertion/JWT generated via my CLI
• Authentication is set to: Body

The thing is that I managed to obtain the access and refresh token, if I did everything manually per documentation via CLI, but I am stuck when it comes to automating it: 3. Make your first API request | Revolut Docs

I would very much apricate if someone would point out the missing piece. Thanks!

Information on your n8n setup

• n8n version: 1.77.4
• Running n8n via (Docker, npm, n8n cloud, desktop app): Cloud

[n8n]

It looks like your topic is missing some important information. Could you provide the following if applicable.

• n8n version:
• Database (default: SQLite):
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• Running n8n via (Docker, npm, n8n cloud, desktop app):
• Operating system:

[Nejc]

Hey everyone, managed to find a dirty solution by skipping n8n’s authentication and just using my refresh tokens directly. Works for now, will see if it breaks later, fingers crossed.

If it helps anyone

[Daniel_Lamphere]

I’ve had a decent amount of issues with n8n’s Oauth2 implementation. Even when using the generic Oauth2 credential type and setting things up correctly. I’ve had tokens not get refreshed for seemingly no good reason, and could prove n8n was not refreshing properly.

This is one of the reasons why I wish n8n would give Variables to everyone, would allow for much easier manual Oauth2 implementations with workflows.

When this happens I setup a refresh workflow and store the tokens somewhere safe and just fetch when needed.