I have developed an agent in Microsoft Copilot Studio and would now like to integrate it into my web application. During development, I used the default “Authenticate with Microsoft” option under the security settings.
However, since the target users belong to a child Azure AD B2C tenant (different from the tenant where the agent is hosted), I need to configure custom authentication.
Based on available documentation and
this community blog, this setup should be done using the “Manual Authentication” option with a Generic OAuth 2.0 provider.
I configured the settings using the B2C OAuth 2.0 endpoints (with a policy), and the authentication flow appears to work correctly — users can log in, receive the authorization code, and the bot displays the greeting message.
The issue arises when a user tries to sends a message. Agent instantly responds with “You don’t have access to talk to this bot. Contact the owner. Error code: AccessToBotDenied.”
My question is: Is it possible to allow users outside my organization (e.g., from a child B2C tenant) to interact with the Copilot Studio agent?
If yes, what is the correct configuration or recommended approach to enable this scenario?
Thank you in advance for your help.
