Unable to add or edit Microsoft Outlook credentials in n8n Describe the problem/error/question When editing or adding a new Microsoft Outlook credential, we are running into the following error message: Error: Client authentication failed (e.g., unknown client, no client authentication included, or…

I am in the same boat, seems to have just happened

You are not along. Two other forum posts have spun up today with this issue. Also there is a forum post from 2 years ago. Only remedy to get you working ASAP is to recreate credentials, and then in all integrations that use credentials switch to the new. Futhermore, this looks to be an issue tha…

N8n - Microsoft Outlook Authentication issue

Questions

Jon December 2, 2025, 2:29am 5

Please see Microsoft Outlook Client authentication failed - #11 by Jon for more info

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N8n - Microsoft Outlook Authentication issue

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