Troubleshooting

My instance won't start

This can happen for a multitude of reasons.

See the following list for some of the most common causes.

Duo doesn't support password-less user accounts.

This is a hard requirement of Network Level Authentication.

The chosen user's password must comply with the host computer's local password policy.

This is by far the most common cause and easily remedied by resetting the user's password and correcting it in Duo Manager.

User accounts that have been linked to a Microsoft account tend to fail Network Level Authentication requests.

Because of this, it is recommended, but not required, to use a separate, dedicated, local user account for your Duo instance.

To create one, follow these steps:

Open the start menu, search for Command Prompt, right-click it, and click on Run as administrator.
Execute the following commands, substituting username and password with your own values:

net user "username" "password" /add /passwordchg:no
net localgroup administrators "username" /add

Once done, update your instance's User Name and Password in Duo Manager.

Duo doesn't support authentication via Kerberos.

Duo captures all of its video data via a custom WDDM driver.

If a group policy forces XDDM drivers, that means Duo's monitor driver will never be able to load properly.

To solve this issue, find the offending group policy and alter it to fit Duo's requirements.

Outdated or corrupted graphic card drivers can cause a range of adapter or encoder related errors that can prevent instances from firing up.

According to Microsoft MSDN this is intentional behavior for DirectX applications inside remote sessions, leaving us with three options:

Run the game in borderless windowed mode (if available).
Run the game in exclusive full-screen mode by translating DirectX to Vulkan via DXVK.
Run the game in windowed mode and use Borderless Gaming to remove the window frame.