Esper SDK returns "SDK UNACTIVATED" for device serial number: delay `activateSDK` call to allow SDK initialization

Android

If your app receives SDK UNACTIVATED as the device serial number when calling the Esper Device SDK, this typically means the SDK service hasn't fully initialized yet. This article explains how to fix this timing issue.

Before you begin

This issue occurs when your app calls esperDeviceSDK.activateSDK() before the Esper SDK service on the device is ready to respond. It's most common at device boot or during early app startup, and the issue resolves on its own within a few minutes. Your API key is valid — this is not an authentication problem.

How to fix this

1. In your app code, locate where you call esperDeviceSDK.activateSDK().
2. Add a 10-second delay before calling activateSDK() during app initialization. This gives the Esper SDK service time to start up on the device.
3. Redeploy or restart your app on the affected device.
4. Check your app logs. Confirm that the device serial number (and other SDK-returned identifiers) now appear correctly without any SDK UNACTIVATED values.

If the issue persists

• Increase the delay: If the 10-second delay doesn't work, try 15 or 20 seconds. The required delay may vary by device model or system performance at boot.
• Implement a retry loop: Instead of treating SDK UNACTIVATED as a permanent failure, wait a few seconds and call activateSDK() again. Continue retrying until you receive a valid device serial number.
• Persistent failures: If SDK UNACTIVATED continues to appear after the boot window, collect the following information and contact Esper Support:
  • How many times activateSDK failed over your testing period
  • Any error codes or exceptions (beyond the SDK UNACTIVATED string)
  • Device model, Android version, and Esper Agent version
  • Timestamps of failures and device uptime at those times

Why this happens

SDK UNACTIVATED is a fallback string returned by the Esper SDK itself (not the Esper backend) when activateSDK() is called before the SDK service is ready. This is a local timing issue on the device, not a credentials or authentication problem. The issue is transient — devices are not permanently affected.

Still need help?

If the steps above don't resolve the issue, contact Esper Support and include the information listed in the "Persistent failures" section above.