Provisioning fails with ERROR-40001328 "Unknown admin" on legacy Android devices: device is not viable for Esper enrollment

Android

If you're seeing error ERROR-40001328 with the message "Unknown admin" during device provisioning, your device may be running an Android version that Esper doesn't support. This article explains why this error occurs and how to resolve it.

What causes ERROR-40001328 "Unknown admin"

Error ERROR-40001328 occurs when the Esper Esper Agent (Esper Agent) cannot register itself as a device admin during provisioning. This typically happens on devices running Android versions older than Android 6.0.

Esper requires the Android Device Policy Manager framework to function, which is only reliably available in Android 6.0 and later. If your device is running an older version of Android, the Esper Agent cannot install or register properly, and provisioning will fail.

Check your device's Android version

On the device, go to Settings → About Device.
Look for the Android Version field and note the version number.
If your device is running Android 5.1 or earlier, it cannot be provisioned with Esper.

Supported Android versions

Esper supports Android 6.0 and later. For the best experience and access to all Esper features, we recommend Android 9 or higher.

Minimum supported: Android 6.0
Recommended: Android 9 or higher
Not supported: Android 5.1 and earlier

How to resolve this issue

If your device is running an unsupported Android version, you have two options:

Update the device OS: If your device manufacturer offers an over-the-air (OTA) update to Android 6.0 or later, install it and retry provisioning.
Replace the device: If no update is available, replace the device with one running Android 6.0 or higher.

Factory resetting the device will not resolve this issue, since the problem is the Android OS version itself, not the device configuration.

Verify device compatibility before provisioning

Before provisioning a device or fleet of devices with Esper, confirm:

Android version is 6.0 or higher.
The device has Google Mobile Services (GMS) or AOSP with Esper Agent support.
The device manufacturer has not restricted Device Owner enrollment.

Still need help?

If you're seeing ERROR-40001328 on a device running Android 6.0 or higher, or if you have other questions about device compatibility, contact Esper Support. For a complete list of supported devices and requirements, see Esper Supported Devices & Requirements.