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Windows Agent | Inspector(s) showing Error: Failed to Send Payload During Inspection

Updated over 3 weeks ago

Overview 💥

Inspectors running on Self-Managed Agents may occasionally fail with the error:

“Failed to send payload during inspection”

This error can occur even after Inspector-specific troubleshooting has been completed successfully. In most confirmed cases, the root cause is a system time mismatch between the Self-Managed Agent host machine and the Liongard platform.

Because Self-Managed Agents rely on time-sensitive authentication, any significant clock skew can cause secure requests to be rejected.


Symptoms 🤒

You may observe one or more of the following:

  • Inspector fails with “Failed to send payload”

  • Inspection does not progress past execution

  • No credential or connectivity errors are shown

  • Issue persists across multiple inspection runs

  • On-Demand Inspectors for the same environment work normally

‼️ This issue only affects Self-Managed Agents. On-Demand Agents are not impacted.


Why Does This Happen? 🤔

Self-Managed Agents authenticate requests to Liongard’s platform using time-based request signing.

If the system clock on the Agent host differs from Liongard’s platform time (UTC) by more than 15 minutes (900,000 milliseconds), the platform rejects the request for security reasons.

This results in a 403 authentication failure, surfaced in the Inspector UI as Failed to send payload.


Key Technical Details 🙌

Item

Value

Max allowed clock skew

15 minutes (900,000 ms)

Authentication type

Time-sensitive signed requests

Affected agent type

Self-Managed Agent only

Common cause

NTP misconfiguration, paused time sync, VM drift


Steps to Resolve 👨‍💻

1️⃣ Initial Troubleshooting (Always Start Here)

Before reviewing logs, perform these baseline steps:

➡ Run Inspector in Debug + Clear Cache Mode

  • Navigate to the affected Inspector

  • Select Run → Debug + Clear Cache

➡ Restart the Liongard Agent Service

  1. Open Services.msc on the Agent host

  2. Locate Liongard Agent

  3. Right-click → Restart

➡ Reinstall the Agent (If Needed)

  • Uninstall the existing agent

  • Download the latest agent installer

  • Reinstall and re-register the agent

✅ If the issue persists after these steps, continue to log verification.

2️⃣ Confirm Time Skew via Agent Logs

On the Agent host machine, navigate to:

C:\Program Files (x86)\Liongard\LiongardInc\logs

Open the most recent error.log file and search for entries similar to the example below.

Sample Error Message

{ "$fault": "client", "$metadata": { "httpStatusCode": 403 }, "Code": "RequestTimeTooSkewed", "MaxAllowedSkewMilliseconds": "900000", "RequestTime": "20250411T132358Z", "ServerTime": "2025-04-11T14:23:59Z", "level": "error", "message": "The difference between the request time and the current time is too large.", "name": "RequestTimeTooSkewed", "stack": "RequestTimeTooSkewed: The difference between the request time and the current time is too large." }

🛑 This confirms a system time mismatch between the Agent and the Liongard platform.

3️⃣ Correct System Time on the Agent Host

➡ Option 1: Command Line Time Sync (Recommended)

Open Command Prompt as Administrator and run:

w32tm /resync

If the command fails, restart the Windows Time service:

net stop w32time
net start w32time
w32tm /resync

➡ Option 2: Windows Settings Time Sync

  1. Go to Settings → Time & Language → Date & Time

  2. Enable Set time automatically

  3. Click Sync now

🔒 Ensure the system can reach a valid NTP source (e.g., time.windows.com).

4️⃣ Rerun the Inspector

Once system time is corrected:

  • Navigate back to the Inspector

  • Run Debug + Clear Cache again

  • Confirm the inspection completes successfully


Environment-Specific Considerations 🧑‍🏫

Domain-Joined Systems

  • Self-Managed Agents typically inherit time from Domain Controllers

  • Verify the DC itself is syncing with a reliable external NTP source

  • A misconfigured DC will propagate incorrect time to all domain members

Virtual Machines

  • VM clock drift is common if host time sync is disabled or paused

  • Ensure hypervisor time synchronization is enabled

Restricted / Air-Gapped Networks

  • Configure synchronization to an internal NTP server

  • Ensure consistent time across all infrastructure components


Best Practices 🤩

  • Enforce time synchronization via Group Policy

  • Monitor NTP health on Domain Controllers

  • Periodically validate system time on Agent hosts

  • Avoid manual time configuration on Agent systems


FAQ's 🙋‍♂️

Q: Does reinstalling the Agent fix this issue?

Not if system time remains incorrect. Time sync must be fixed first.

Q: Can firewall or proxy issues cause this error?

No. This error specifically indicates authentication rejection due to time skew.

Q: Will this affect all inspectors on the agent?

Yes. Any inspection using that Self-Managed Agent may fail until time is corrected.


When to Contact Support 🦁

If the issue continues after correcting system time, contact Liongard Support.

Please include the following when opening a ticket:

  • Agent OS version

  • Agent version installed

  • Inspector type(s) affected

  • Screenshot of the Inspector error

  • Relevant error.log entries

  • Confirmation that system time is synced and current


Summary 🌟

  • “Failed to send payload” on Self-Managed Agents is commonly caused by system time skew

  • Liongard enforces a 15-minute maximum clock difference

  • Logs will show RequestTimeTooSkewed (403) when this occurs

  • Correcting system time resolves the issue

  • Enforcing reliable NTP sync prevents recurrence

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