N8n Cloud Slack "Forbidden" error

Hi n8n folks!

I am using n8n.cloud 0.123.1 , and when I go to authenticate to slack via OAuth, it seems to work fine.

However, when I try to do anything, post a message, get all channels, I just get:

" There was a problem running the workflow:
Forbidden - perhaps check your credentials?"

Details say: Box Trigger: 403 - undefined

Is anyone else having this same issue.

I have the same problem on my instance with the Box trigger/Box node as well. Same behaviour.

Side note, I have also filed a cloud support request.


Hey Will,

This is a known issue and I am working on a fix :slight_smile:

In the meantime, you can use the Access Token authentication method. Let me know if you need any help

Thanks, I just got it to work via the token. I also had the box trigger in front of it, and it was causing a problem as well for slack.

Slack works now, having added all the scopes. I will continue to look at box.


Harshil, did you also mean that the Box node has a known issue. I’m getting Box Trigger: 403 - undefined as an error.

Also, I upgraded my node to 0.124.1. I can go to 0.126.1 if that might help.


There seems to be a bug in the Box Trigger node. The credentials work fine in the regular node. @RicardoE105 can you take a look at this?

The Box Trigger node gives an error, but the same credentials are working for the regular node.

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Curiously, having the box trigger node in the same workflow as any other node (including slack and regular box) causes them all to fail in “manual” execution mode for any single node. (pressing the workflow execute on just the slack node for instance.)

Hope this helps on diagnosing the issue.


Are your nodes still connected to the Box Trigger node? If yes, then n8n is waiting for the Box Trigger node to get executed. Since the node is giving an error, the next nodes in the workflow also don’t get executed. Disconnect the node from the Box Trigger node and/or disable the Box Trigger node.