# Connection troubleshooting > Troubleshooting steps for Robot connection issues with Orchestrator, including authentication errors and tenant configuration problems. ## Interactive sign-in is not enabled for this tenant ### Description The tenant you are trying to access does not have authentication enabled. ### Potential issue The tenant's attended robot authentication doesn't allow user sign-in. This can happen on tenants created in an older version of Orchestrator, before interactive sign-in was available. ### Solution The proposed solution must be performed by an Orchestrator administrator: 1. In Orchestrator, go to **Tenant** > **Settings**, and open the **Robot security** tab. 2. In the **Robot authentication** section, set attended robot authentication to **Interactive Sign-in SSO**. Choose **Hybrid** instead only if attended robots still connect with a machine key. 3. Select **Save**. For the options, refer to [Robot authentication](https://docs.uipath.com/orchestrator/automation-cloud/latest/user-guide/robot-authentication). ## Interactive connect is not available ### Description You cannot connect through the Interactive Sign-In. ### Potential issue The Robot is installed in Service Mode. ### Solution When the Robot is installed in Service Mode, connect the service using client credentials first, then proceed with Interactive Sign-In (Service URL). ## Robot does not exist ### Description You receive the error message "Robot does not exist". ### Potential issue You might be using a classic robot, which was defined in Orchestrator using the classic method or via the Windows user, and you are already connected to Orchestrator with a machine key. When you then sign in from Studio, a different username is sent to Orchestrator. This applies only to robots connected with a machine key. ### Solution The proposed solution must be performed by an Orchestrator administrator: * In Orchestrator, set up a modern robot, then sign in again. ## Cannot acquire a license ### Description You receive the error message "Cannot acquire a license". ### Potential issue Your user account is not properly configured to acquire a license from Orchestrator. ### Solution The proposed solution must be performed by an Orchestrator administrator: * In Orchestrator, edit the problematic user account to execute attended automations, then assign it an Attended license. To verify the license availability, go to **Tenant** > **License**. ## No such host in known ### Description You receive the error message "No such host in known". ### Potential issue Connection to Orchestrator could not be established. ### Solution Verify that your Internet connection is working. ## You are not authorized to perform this action ### Description You receive the error message "You are not authorized to perform this action". ### Potential issue The user connected with the machine key associated with one tenant, but then tries to sign in to a different tenant. ### Solution For User Mode installations, sign in using the service URL. For Service Mode installation, sign out from the Assistant, then sign in again. ## Could not start executor in an RDP setup ### Description You receive the error message "Could not start executor. Please ensure the user is allowed to access the computer via Remote Desktop. Original message: Rdp connection failed: ... Last error: 131085". ### Potential issue The user account used to run the unattended automation runs was not added to the **Remote Desktop Users** group. ### Solution Add the user account to the **Remote Desktop Users** group. For details, see [User permissions to run automations](https://docs.uipath.com/robot/standalone/2026.10/admin-guide/prerequisites-unattended-installation#for-unattended-automations). ## Robot cannot connect to an Automation Suite Orchestrator instance ### Description When trying to connect or sign in to an Orchestrator provided with Automation Suite 2024.10, you may encounter this error: "System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception." This issue affects Windows 10. ### Potential issue Automation Suite 2024.10, which hosts the Orchestrator instance you want to connect to, [uses TLS 1.3 by default](https://docs.uipath.com/automation-suite/automation-suite/2024.10/release-notes/automation-suite-2024-10-0#support-for-tls-13). Windows 10 does not support this version. ### Solution You have two options: * [Configure Automation Suite 2024.10 to use TLS 1.2](https://docs.uipath.com/automation-suite/automation-suite/2024.10/installation-guide/how-to-address-weak-ciphers-in-tls-12) instead, or * Use an operating system other than Windows 10.