Windows Device Health Attestation Failure

Question

Windows Device Health Attestation Failure

Sarah 20

Laptops fail conditional access checks due to failed Device Health Attestation. How do we verify TPM 2.0 status, Secure Boot, and DHA endpoint access?

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2 answers

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Answer 1

Use this verification path on an affected laptop:

Check TPM version.
- Press Win + R, run tpm.msc.
- In TPM Management on Local Computer, check Specification Version.
- Device Health Attestation supports devices with TPM 1.2 or 2.0, but for Intune health attestation compliance checks, if the device is on TPM 1.2 and supports TPM 2.0, update to TPM 2.0.
Verify UEFI and PCR7 binding.
- Open an elevated Command Prompt and run msinfo32.
- In System Summary, confirm:
  - BIOS Mode = UEFI
  - PCR7 Configuration = Bound
- A computer with legacy BIOS and TPM 2.0 will not work as expected for this scenario.
Verify Secure Boot state.
- Open an elevated PowerShell window and run:
```
     Confirm-SecureBootUEFI
```
- Expected result: True.
Verify BitLocker PCR protection.
- Run:
```
     manage-bde -protectors -get $env:systemdrive
```
- Confirm the system drive is protected by PCR 7.
Verify DHA service connectivity.
- Both the device and the MDM server must be able to reach has.spserv.microsoft.com over TCP 443 (HTTPS).
- If that endpoint is unreachable, health attestation validation can fail.
Check DHA/HealthAttestation errors if connectivity is suspected.
- Relevant HealthAttestation CSP errors include:
  - 30 = failed to send HTTP request
  - 31 = failed to receive response
  - 32 = failed to query HTTP headers
  - 33 = empty response with HTTP OK
  - 34 = empty response with HTTP error
  - 404 = DHA service endpoint not reachable
Validate what DHA reports to MDM.
- Health Attestation can provide MDM with device state such as:
  - Secure Boot enabled
  - BitLocker enabled
  - ELAM loaded
  - Boot and kernel debug enabled/disabled
  - VSM enabled
  - TPM provisioned with a trusted endorsement certificate
- Conditional access decisions depend on the MDM evaluating that attestation state and updating device compliance in Microsoft Entra ID.

If devices still fail conditional access after these checks, focus on mismatches in TPM version, UEFI/PCR7 state, Secure Boot result, or blocked access to has.spserv.microsoft.com:443.

References:

Answer 2

Hello,

When laptops fail conditional access checks due to Device Health Attestation (DHA), the root cause is usually one of three things: TPM 2.0 not being active or ready, Secure Boot not being enforced, or the client failing to reach the DHA service endpoint. Each of these needs to be verified systematically.

For TPM 2.0, open an elevated PowerShell session and run Get-TPM. The output should show TpmPresent: True, TpmReady: True, and SpecVersion: 2.0. If the TPM is present but not ready, you may need to clear and reinitialize it from the BIOS/UEFI firmware settings. Also confirm that the BIOS is not set to “Discrete TPM disabled” or “Firmware TPM off.”

For Secure Boot, check with Confirm-SecureBootUEFI. If the command returns True, Secure Boot is enabled. If it returns False or throws an error, you need to enable Secure Boot in the UEFI firmware. Note that Secure Boot requires UEFI mode; if the machine is running in legacy BIOS mode, it cannot be enabled.

For DHA endpoint access, the client must reach the Microsoft Health Attestation Service. The endpoint is https://attestation.microsoft.com. In an enterprise environment, conditional access policies rely on the device submitting its health report to this service. If the laptops are behind a proxy or firewall, ensure outbound HTTPS traffic to that endpoint is allowed. You can test connectivity with Test-NetConnection attestation.microsoft.com -Port 443. If this fails, the device cannot complete health attestation and will be blocked.

In practice, the verification sequence is: confirm TPM 2.0 is active and owned, confirm Secure Boot is enabled, and confirm the client can reach the DHA endpoint. If all three are correct, the device should pass conditional access checks. If any of these fail, remediation must be done at the firmware or network level before the device can be considered compliant.

I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!

Domic Vo.