Error code occurs when running an attended or unattended desktop flow

This article provides the mitigation steps for the error codes that occur when running attended or unattended desktop flows.

Applies to:   Power Automate
Original KB number:   4555406

Note

If the error code that you receive is not listed in the table, contact Power Automate support.

Error code HTTP status code Run mode Mitigation steps
UnsupportedRpaScriptSchemaVersion 400 Attended
Unattended
The selected flow was issued by a later version of Power Automate for desktop. You'll need to install the latest version of Power Automate for desktop on your machine.
InvalidUIFlowsCertificates 401 Attended
Unattended
You'll need to install the latest version of desktop flows on your machine as the security certificate of the desktop flows app has expired.
WindowsIdentityIncorrect 401 Attended
Unattended
Check that you can sign in to the machine using the connection credentials. Below are supported format:
- domain\username -> domain account (domain and Microsoft Azure Active Directory (Azure AD))
- username@domain... -> Azure AD account
- username -> local account
- machine name\username -> local account
- local\username -> local account
- .\username -> local account
NoUnlockedActiveSessionForAttended 400 Attended Check that you're logged in with the correct user and that the session is unlocked on the machine.
SessionCreationError 400 Unattended Check requirements for unattended scenario:
- The user specified in your connection is a member of the Remote Desktop Users group.
- Remote Desktop is enabled on the computer.
SessionCreationWinLogonFailure 400 Unattended We can't create a Windows session to run your unattended desktop flow. You need to restart your machine.
SessionExistsForTheUserWhenUnattended 400 Unattended Check that you aren't logged in with the same user (regardless of the state of the session) on the machine.
TooManyActiveSessions 400 Unattended Windows Server only.
You need to sign out at least one active session on the machine.
ExistingRecordingSession 400 Local Windows Server only.
Check that there's no other user connected to the machine launching a recording or a test playback.
LocalPlaybackOrRecordingOngoing 429 All Check that there's no recording nor test playback ongoing on the machine for the same user session.
UnattendedUnsupportedWithOldConnection 403 Unattended You need to create a new connection on the portal.
RDPIsNotEnabled 400 Unattended You need to enable Remote Desktop on the machine.
UIFlowAlreadyRunning 429 Attended
Unattended
A desktop flow is already running on the machine. You need to wait for its completion.
AadLogonFailure 400 Unattended You need to disable Network Level Authentication (NLA) on the machine if you want to use Azure Active Directory (Azure AD) credentials.
Win10AlreadyHasActiveSession 400 Unattended Windows 10 only. You need to sign out from the active session on the machine.
UIFlowAgentNotAvailable 400 Attended
Unattended
You need to confirm that the service uiflowservice is up and running on your machine. If you have the following error when trying to start uiflowservice, see Desktop flows failure:
Windows could not start the UIFlowService service on Local Computer. Error 1069: The service did not start due to a logon failure
UnableToCallCrlEndpoint 400 Attended
Unattended
You need to ensure the revocation list for the certificates can be checked. Ensure that the CRL services aren't blocked on the target machine. The services that must be contacted are listed in this article: Limits for automated, scheduled, and instant flows
NoListenerConnected 404 Attended
Unattended
The endpoint wasn't found. There are no listeners connected to the endpoint.
Check that your machine is online.
ConnectionNotEstablished 404 Attended
Unattended
The endpoint wasn't found. None of the connected listeners accepted the connection within the allowed timeout.
This error code can be caused by routing or firewall configuration issues. Check that your machine is online and can communicate with the required Power Automate endpoints.
DnsError 404 Attended
Unattended
The endpoint wasn't found.
Register your machine again and schedule new runs.
ConnectionTimeout 404 Attended
Unattended
This request operation didn't receive a reply within the configured timeout.
Check that your machine is online and can communicate with the required Power Automate endpoints.
EndpointDoNotExist 404 Attended
Unattended
The endpoint wasn't found.
Register your machine again and schedule new runs.
GroupIsEmpty 400 Attended
Unattended
The machine group is empty.
Add machines to the group, then reschedule new runs.
NoCandidateMachine 400 Attended
Unattended
The run has exceeded the queue waiting time limit.
Consider allocating more machines or spreading desktop flow runs to optimize wait time in the queue.
DesktopFlowsActionThrottled 429 Attended
Unattended
The desktop flow action failed because of throttling. This error code appears when too many desktop flows use the same connection.
Check your connection usage and assign your desktop flows to multiple connections.
DesktopFlowsActionTimeout 400 Attended
Unattended
The execution of the desktop flow action exceeded maximum duration.
Increase the time-out value that's set on the action or split the desktop flow into several shorter desktop flows.