Webhook to slack throws TypeError error

Webhook to slack throws the following error: ERROR: Cannot convert undefined or null to object
TypeError: Cannot convert undefined or null to object.

It seems like something is wrong with the way the object is being passed by the webhook or the oauth with slack is having some problems (see both attachments).

Couldn’t find any more details at the moment in our logs because we still have to set up that part of the n8n environment.


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Is this a bug or a problem on our side?

Thank you in advance.

Sadly impossible to say without more information. Can you please post the workflow which throws that error. Also which node does error? Is it the Webhook or the Slack one?
Seems to have to do with some kind of expression that is set somewhere (at least that is where the error is thrown).

image

This is the workflow. The webhook receives the following body:
“body”: {
“value1”: “this_value”,
“value2”: “this_value”
}

And the slack node throws this error:

ERROR: Cannot convert undefined or null to object

TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at Expression.getParameterValue (/usr/local/lib/node_modules/n8n/node_modules/n8n-workflow/dist/src/Expression.js:94:38)
    at resolveParameterValue (/usr/local/lib/node_modules/n8n/node_modules/n8n-workflow/dist/src/Expression.js:73:29)
    at Expression.getParameterValue (/usr/local/lib/node_modules/n8n/node_modules/n8n-workflow/dist/src/Expression.js:95:35)
    at resolveParameterValue (/usr/local/lib/node_modules/n8n/node_modules/n8n-workflow/dist/src/Expression.js:73:29)
    at Expression.getParameterValue (/usr/local/lib/node_modules/n8n/node_modules/n8n-workflow/dist/src/Expression.js:95:35)
    at Expression.getComplexParameterValue (/usr/local/lib/node_modules/n8n/node_modules/n8n-workflow/dist/src/Expression.js:64:33)
    at CredentialsHelper.applyDefaultsAndOverwrites (/usr/local/lib/node_modules/n8n/dist/src/CredentialsHelper.js:66:45)
    at CredentialsHelper.getDecrypted (/usr/local/lib/node_modules/n8n/dist/src/CredentialsHelper.js:50:21)
    at getCredentials (/usr/local/lib/node_modules/n8n/node_modules/n8n-core/dist/src/NodeExecuteFunctions.js:184:66)

I’m using the oauth2 authentication method for Slack.

Is this more helpful? I’m trying to get some server error logging this way but I’m not sure if I can get it today.

A little bit. Can you please select the Slack node, copy (ctrl + c) and then paste it here (ctrl + v). That I can see what exactly is set on the node. Thanks!

And did you create an App within Slack and set the displayed Client ID and Client Secret in the credentials?

Ignore my messages. I can reproduce and will check what is going wrong.

A new version with a fix just got released. Please use n8n@0.84.0

Thank you, will update to 0.84.1 and let you know the result!

It’s working again, thanks for the fast work!