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Power Automate Connection Error (401 Unauthorized)

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Ongoing Web Updated November 14, 2026Based on 4 user reportsHow we research

Quick answer

A previously working flow that now returns 401 Unauthorized usually has an expired or broken connection. Go to Connections, select Fix connection and sign in again.

Most likely fix: Re-authenticate the connection

How to fix it

Try these in order — the most common fix is first.

  1. 1. Re-authenticate the connection

    1. Open Power Automate > Connections
    2. Find the connection with the error
    3. Select ... > Fix connection or Edit and sign in again
    4. Open the flow and confirm the action shows a green checkmark
    Did this fix it?

  2. 2. Fix Conditional Access mismatches

    1. In Microsoft Entra admin center go to Protection > Conditional Access > Policies
    2. Target the Office 365 app or All cloud apps
    3. If targeting individual apps include Microsoft Flow Service
    4. Exclude service accounts from Terms of Use policies
    Did this fix it?

  3. 3. Stop it recurring

    1. Use a service principal connection for production flows
    2. Ask the connection owner to re-authenticate shared connections, or create your own
    Did this fix it?

Symptoms

Actions show Unauthorized, 401 or 403 and the connection shows a warning icon.

Why it happens

  • Password changed or rotated
  • MFA or Conditional Access policy changed
  • Admin consent revoked
  • Refresh token expired after about 90 days of inactivity
  • Service principal secret expired
  • Connection owned by someone who left

This guide also covers

  • power automate connection error
  • power automate unauthorized 401
  • power automate fix connection

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