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The RDS CAL license code is not being recognized.

38698314 20 Reputation points
2026-03-31T01:15:57.4266667+00:00

When I tried to register the Windows Server 2016 RDS CALs (User CALs) on Windows Server 2012 R2 using the "Automatic connection" method, the following error appeared: "The license code is not recognized. Please verify that the correct license code was entered."　There is no error in the license code I entered.

Windows for business | Windows Server | User experience | Remote desktop services and terminal services
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  1. Harry Phan 17,205 Reputation points Independent Advisor
    2026-03-31T01:30:32.0233333+00:00

    Hi,

    The error occurs because RDS CALs are version‑locked: Windows Server 2016 RDS CALs cannot be installed on a Windows Server 2012 R2 license server. The license server must be at least the same version as the CALs you are trying to register, or newer. In your case, the 2012 R2 license server simply does not recognize 2016 CALs, which is why the code is rejected even though it is correct.

    To resolve this, you need to upgrade your Remote Desktop Licensing server to Windows Server 2016 or later, then install the 2016 User CALs there. Once the CALs are registered on a 2016 license server, they can issue licenses to 2016 RDS session hosts. There is no supported method to back‑port newer CALs to an older license server. If you must keep 2012 R2 as the host OS, you will need to obtain 2012 R2 CALs instead. This is a strict Microsoft licensing requirement, not a technical misconfiguration.

    Let me know you need further assistant, please feel free to hit accept answer if you find this information helpful to you.

    Harry.

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  1. Q&A Assist
    2026-03-31T01:16:06.7533333+00:00
    AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

    Windows Server 2016 RDS User CALs cannot be installed on a Windows Server 2012 R2 Remote Desktop license server. The license program rejects the code because the CAL version is newer than the license server/OS version.

    To resolve this, use one of the following supported options:

    1. Install and activate the RDS license server on a supported OS version for 2016 CALs (for example, Windows Server 2016 or later), then install the Windows Server 2016 RDS User CALs there.
    2. If the RDS license server must remain on Windows Server 2012 R2, use RDS CALs that are compatible with that version (for example, 2012 R2 CALs) instead of 2016 CALs.

    After installing the CALs on a compatible license server, configure the RD Session Host/RDS deployment to use that license server and the correct licensing mode (Per User) via Server Manager → Remote Desktop Services → Edit Deployment Properties → RD Licensing.

    References:

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