User Binding Error Causes Mobile VPN with SSL Connection Failures

Applies To: Cloud-managed Fireboxes This topic applies to Fireboxes you configure in WatchGuard Cloud., Locally-managed Fireboxes This topic applies to Fireboxes you configure in Policy Manager or Fireware Web UI.

When you configure Mobile VPN with SSL to authenticate users with an Active Directory or LDAP server, the Firebox must successfully bind to the directory and search for the user account. If the Firebox cannot complete the required bind or search operation, the authentication attempt fails and the Firebox rejects the connection.

Symptoms

When a user binding error occurs, you might notice these symptoms:

• VPN connection attempts fail immediately.
• The user might authenticate successfully to other services, depending on the directory configuration.
• Other users might be affected, depending on directory permissions.
• Firebox admd log messages show messages show a user binding error. Examples:
  • admd Authentication of SSLVPN user [[email protected]] from x.x.x.x was rejected, user binding error,check your username or password msg_id="1100-000"
  • admd[2929]: admLdapSessBindingChkResult: binding error:Strong(er) authentication required
  • admd[2929]: admLdapSessBindingChkResult: more binding error:00002028: LdapErr: DSID-0C090343, comment: The server requires binds to turn on integrity checking if SSL\TLS are not already active on the connection, data 0, v65f4
  • admd[2929]: Auth for [email protected] result=3 ec=11(Ldap binding not successful) msg=search binding error, check your searching username or password
  • admd[2929]: msg_id="1100-0005" Authentication of Firewall user [[email protected]] from console was rejected, search binding error, check your searching username or password
  • admd[2929]: admLdapSessFSM: failed to parse binding result, rc=11

Diagnostic Steps

1. Verify that the user credentials are correct.
2. If possible, verify that the user can use the same credentials to log in to another system that uses the same Active Directory or LDAP server for authentication.
3. Consider recent directory configuration changes.
• Have there been recent security hardening changes to the domain?
• Have the default user permissions been changed?
4. Verify directory permissions for the user account and make sure that the user has these minimum required permissions:
   • Read all user information
   • Read group membership
   • List contents of the container (the domain or organizational unit that contains users and groups)
   Verify directory permissions in Active Directory.

   1. Open Active Directory Users and Computers.
   2. Enable View > Advanced Features.
   3. Right‑click the domain or target organizational unit and select Properties.
   4. Go to Security > Advanced > Effective Access (or Effective Permissions in older Windows Server versions).
   5. Select the affected user or group and review the effective permissions.
   6. Verify that the user or group can perform the required read and search operations.
5. For Active Directory authentication, verify LDAP channel binding and signing requirements in the Windows Server settings. Some Windows Server configurations require LDAP channel binding or LDAP signing, which can block authentication if the Firebox configuration is not compatible.
   1. On the Windows Server, open Group Policy Management Editor.
   2. Go to Default Domain Controller Policy > Computer Configuration > Policies > Windows Settings > Security Settings > Local Policies > Security Options.
   3. Verify these settings:
      • Domain controller: LDAP server channel binding token requirements
      • Set Domain controller: LDAP server signing requirements
      • Set Domain controller: LDAP server enforce signing requirements
      • Set Network Security: LDAP client encryption requirements
      • Set Network security: LDAP client signing requirements

Possible Causes and Solutions

Possible Cause	Solution
The user entered incorrect credentials in the Mobile VPN with SSL client.	Confirm that the user has the correct user name and password. If necessary, reset the password on the authentication server.
The user lacks required LDAP or Active Directory permissions.	Restore required Active Directory or LDAP permissions. Review and reverse recent hardening changes that affect permissions, if appropriate. If you cannot grant the affected user the required permissions, configure a Searching User in the Firebox Active Directory or LDAP authentication settings. A searching user is a directory account that the Firebox uses to perform LDAP or Active Directory search operations. When configured, the Firebox performs directory searches with the searching user account, rather than the permissions of the user account under authentication. The account specified must be in Distinguished Name format. The account should be set up in Active Directory or LDAP as a service account and must have the necessary permissions to perform binds and searches. For more information, go to: Locally-Managed with Active Directory: Configure Active Directory Authentication Locally-Managed with LDAP: Configure LDAP Authentication Cloud-Managed with Active Directory: Configure Active Directory Server Settings
(Active Directory only) LDAP channel binding or signing is enforced without compatible Mobile VPN with SSL settings.	Disable LDAP client encryption on Windows Server or set up LDAPS for the authentication server. For more information, go to the knowledge base article Active Directory authentication fails with message "binding error:Strong(er) authentication required" after upgrade to Windows Server 2025 or when LDAP client encryption is enforced.

Related Topics

Resolve a Bind Error in Active Directory Authentication

Find Your Active Directory Search Base

Troubleshoot Mobile VPN with SSL

About Mobile VPN with SSL