> Source: [sk166072](https://support.checkpoint.com/results/sk/sk166072)

# sk166072 - Endpoint Security Client cannot connect to Endpoint Security Server when Active Directory domain is not reachable

| Property | Value |
|----------|-------|
| Solution ID | sk166072 |
| Date Created | 2020-04-09 |
| Last Modified | 2020-06-08 |
| Technical Level | Advanced |
| Products | Endpoint Security |
| Versions | Cloud, E89.X, E88.X |
| OS | Windows, macOS |

## Symptoms

- * Endpoint Security Client cannot connect to Endpoint Security Server when Active Directory domain is not reachable.
* "EndPoint security client cannot register to the server. The security ID of this machine was not found. Contact your administrator" error message is displayed in Endpoint Security Client's UI.
* Error message from %PROGRAMDATA%\\CheckPoint\\Logs\\cpda.log:

  ```
  
  DATE TIME t:6000 root [error ] LoadAccount using account: XXXXXXXXXXX$, failed. Error: 1789 [g_getCompSIDBySpecificName]
  DATE TIME t:6000 root [debug ] Going to try NetBios account name: XXXXXXXXXXX$, to find SID [g_getNetBiosCompAccountName]
  DATE TIME t:6000 root [error ] LoadAccount using account: XXXXXXXXXXXX$, failed. Error: 1789 [g_getCompSIDBySpecificName]
  DATE TIME t:6000 root [warning ] No Sid retrived [g_getCompSID]
  DATE TIME t:6000 root [warning ] UpdateRegister: Failed to get computer SID, no update register will be sent [CDA::checkUpdateRegisterRequired]
  ```

## Cause

Unplanned effect of a more strict behavior on domain SID checking.

## Solution

This solution requires authentication. Please log in to view the full solution.

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