Power Automate "connection expired" / 401 Unauthorized
A 401 or "connection has expired" error means the stored connection behind that connector can no longer authenticate — the credential expired, the password changed, or consent was revoked. Immediate fix: open the failing action, check its connection, then in Power Automate > Connections find the broken one and click "Fix connection" or re-authenticate. Durable fix: run production flows on a dedicated service account whose password policy doesn’t force expiry, or use a connection type that supports long-lived authentication, so the connection doesn’t break when someone changes their password or leaves.
Why it happens
Each connector in a flow uses a stored connection (a set of credentials). When the credential expires, the password changes, or consent is revoked, the connection can no longer authenticate and the action fails with 401.
How to fix it
- 1Open the flow, then go to the failing action and check the connection at the bottom of the action card.
- 2In Power Automate > Connections, find the broken connection (it shows an error) and click "Fix connection" or re-authenticate.
- 3If you use a service account, make sure its password policy does not force expiry, or move to a connection that supports long-lived auth.
Prevent it
Use a dedicated service account for production flows rather than a personal account, so the connection does not break when someone changes their password or leaves.