Wi-Fi Authentication Fails After Clock Drift: Manually Sync Time via Open Network to Recover

Android

If your device shows "no network" or fails to connect to your Wi-Fi network after being offline for an extended period, the device's system clock may have drifted out of sync. This is especially common with certificate-secured Wi-Fi networks, which require an accurate device clock to authenticate. Follow these steps to resync your device's time and restore connectivity.

Before you begin

This issue occurs when:

• Your device has been offline (powered on but without internet) for several hours or overnight.
• Your target Wi-Fi network uses certificate-based authentication (WPA2-Enterprise or 802.1X).
• Your device cannot sync its clock because it's not connected to any network yet.

Step 1: Verify the device is offline

1. Open the Esper Console.
2. Navigate to Devices & Groups → [Device Name] → Device Information.
3. Confirm the device status shows Offline.

Step 2: Connect to a temporary open network

1. On the device, open Settings → Network & Internet → Wi-Fi.
2. Select an open or password-protected network that has internet access. Examples include:
   • A mobile hotspot
   • A guest network
   • Any publicly available Wi-Fi
3. Connect to this network. Do not disconnect until your clock is synced.

Step 3: Allow time for automatic clock sync

1. Wait 30–60 seconds for Android to sync your device clock via NTP (Network Time Protocol).
2. Go to Settings → System → Date & Time.
3. Verify that your device now displays the correct date, time, and timezone.

Step 4: Connect to your target Wi-Fi network

1. Return to Settings → Network & Internet → Wi-Fi.
2. Forget or disconnect from the temporary network.
3. Select your target certificate-secured network (for example, "Finishline").
4. Enter your credentials and authenticate. The connection should now succeed.

Step 5: Verify the device is online

1. On the device, confirm that you now have an active internet connection.
2. In the Esper Console, navigate to Devices & Groups → [Device Name] → Device Information.
3. Confirm that:
   • Device status changed from Offline to Online
   • Network details show the correct SSID and a valid IP address

Troubleshooting

Your clock synced but authentication still fails:

• Contact your network administrator to verify that your RADIUS server certificate and any intermediate or root CA certificates are still valid and have not expired.

Your clock will not sync via NTP:

• Verify that the temporary open network allows outbound access to UDP port 123 (required for NTP).
• Try a different open network with less restrictive firewall rules.

Multiple devices are affected at the same time:

• In the Esper Console, check whether automatic time sync is enforced: navigate to Blueprints → [Blueprint Name] → Device Settings → Date & Time and verify that automatic time sync is enabled.
• If automatic time sync is already enabled but the issue persists, contact Esper Support and provide the following details:
  • Number of devices affected
  • How long the devices were offline before the issue occurred
  • Device model and Android OS version

The issue happens repeatedly:

• Contact Esper Support with:
  • Approximate number of affected devices
  • How often the issue recurs
  • Device model/OEM and Android OS version
  • How long devices are typically offline before failure
• Esper Support can help configure periodic network connectivity or scheduled reboots via your device Blueprint to prevent clock drift.

Still need help?

If you've followed all steps above and your device is still offline or unable to authenticate, submit a support ticket. Include your device serial number, the target Wi-Fi network name, and the steps you've already tried.