Device offline in Esper Console despite confirmed network reachability: correct system time and restore NTP connectivity

Android

If your device appears offline in the Esper Console but is reachable on your network, the issue is often a system time synchronization problem. Your device's clock must stay accurate for secure communication with Esper's servers. This article shows you how to fix time synchronization issues and bring your device back online.

Before you begin

Verify that your device is reachable on your network (ping succeeds, SSH connects) before following these steps. If the device is unreachable, contact your network administrator first.

Step 1: Check your device's system time

Use SSH or ADB to connect to your device and check its current system time:

date

Compare the output to the actual current time. If the time is significantly off (more than a few minutes), this is likely causing your connectivity issue.

Step 2: Correct the system time

You can correct the time in two ways:

Using the command line: SSH into the device and run:
```
date -s "YYYY-MM-DD HH:MM:SS"
```
Replace the string with the current UTC time.
Using the device UI: Go to Settings → System → Date & Time, toggle off automatic time sync, then toggle it back on. Or set the time manually in this menu.

Step 3: Restore NTP server connectivity

Your device syncs time automatically through an NTP (Network Time Protocol) server. If your device cannot reach its NTP server, the clock will drift over time and cause disconnection issues.

Check whether your device can reach its NTP server:

ntpdate -q pool.ntp.org

If this command fails, your network may be blocking NTP traffic. Verify that:

Outbound UDP port 123 is not blocked by your firewall
Your DNS can resolve the NTP server hostname
Your network allowlist (if you have one) includes NTP servers

Work with your network administrator to unblock port 123 if needed.

Step 4: Verify automatic time sync is enabled

After NTP connectivity is restored, confirm that automatic time synchronization is turned on in your device settings. This ensures your clock stays accurate going forward.

Step 5: Verify the device comes back online

Check the Esper Console by navigating to Devices & Groups → Device Details for your device. The device status should change from offline to online within a few minutes. The last-seen timestamp should update to the current time.

If the device still doesn't come online

If correcting the system time doesn't restore your connection:

Restart the Esper agent service:
```
adb shell am force-stop com.example.app
adb shell am start com.example.app
```
(The package name may vary depending on your Esper agent version.)
Test Esper connectivity: Verify that your device can reach Esper's cloud endpoints:
```
curl -v https://your-tenant.esper.io
```
If this fails, check whether a proxy, firewall, or certificate issue is blocking Esper traffic.
Check agent logs: Look for TLS errors in the Esper agent logs:
```
adb logcat -s EsperDPC
```

Still need help?

If your device remains offline after correcting the system time and restarting the agent, contact Esper Support. include:

The device's current system time and the correct time
The output of adb logcat -s EsperDPC
Your Esper agent version
Your network configuration (whether you use NTP allowlists or firewall rules)