All Copilot Studio Workflow Tools Suddenly Returning HTTP 403 Before Execution

Hello Copilot Studio Community,

I am experiencing an authorization issue with multiple workflows connected to an agent built using the Copilot Studio new experience and new Workflows experience.

These workflows worked successfully for multiple users yesterday. Today, all workflow tools connected to the agent began returning an immediate HTTP 403 authorization error. I did not intentionally change the agent, workflows, environment, or workflow permissions before the issue started.

Error message:

You don’t have permission to use this tool. You’re signed in, but access to this resource is blocked.

Error details: Authorization - 403

Example error information:

Status: Failed

Error message: Flow returned HTTP 403

Error code: Http403

Inner error code: NotSpecified

Tool duration: Approximately 93 milliseconds

Configuration:

- Copilot Studio new agent experience

- Copilot Studio new Workflows experience

- Agent and workflows are in the same Power Platform environment

- Workflows use the "When an agent calls the workflow" trigger

- Each workflow includes a "Respond to the agent" action

- Workflows are saved and published

- Agent is saved and published

Observed behavior:

The problem affects several independent workflows, including:

- New-request submission

- Current-user identity resolution

- Approval decisions

- Requester justification

- Executive decisions

- Fulfillment updates

For every affected workflow:

- The agent fills the workflow inputs correctly.

- The tool call fails almost immediately.

- No corresponding run appears in the workflow Activity history.

- The workflow trigger is never reached.

- No workflow actions execute.

Because no workflow run is created, the rejection appears to occur before workflow execution, possibly within the Copilot Studio agent-to-workflow authorization or invocation layer.

Troubleshooting already completed:

- Confirmed that all workflows are published.

- Confirmed that the agent is published.

- Tested in a completely new conversation.

- Removed an affected workflow tool from the agent.

- Saved the agent.

- Added the same published workflow back to the agent.

- Reconfigured and verified the tool inputs.

- Republished the agent.

- Confirmed that no workflow Activity run is created.

- Confirmed that the issue affects multiple workflows rather than one specific workflow.

Removing and re-adding the workflow did not resolve the problem.

Questions for the community:

1. Is anyone else currently experiencing HTTP 403 errors when Copilot Studio agents invoke workflows?

2. Is this a known issue or regression in the new Workflows experience?

3. Is there an environment-level or tenant-level permission that controls agent-to-workflow invocation?

4. Could a tenant policy, Conditional Access change, service principal, connection reference, or workflow-sharing configuration cause all workflow tools to fail simultaneously?

5. Where can an administrator find detailed authorization logs when the workflow never creates a run?

6. Has anyone found a workaround for this issue?

Any guidance or confirmation from others experiencing the same behavior would be appreciated. I can provide screenshots, complete error details, timestamps, and additional configuration information if needed.

Thank you.