Fix LDAP Connection Error 81: Cannot open connection via the ldp.exe tool

Configuring Secure LDAP for a Domain Controller

This guide teach you how to fix LDAP connection error. With LDP, you can perform operations such as connect, bind, search, modify, add, and delete against any Lightweight Directory Access Protocol (LDAP)-compatible directory, such as Active Directory Domain Services (AD DS). LDP is an LDAP client that you use to view objects that are stored in AD DS along with their metadata, such as security descriptors and replication metadata. Kindly refer to the following related guides: “The application /Certsrv does not exist: How to configure Certificate Enrollment Web Services and Certificate Authority Web Enrollment“, How to import a certificate into the Trusted Root and Personal file certificate store, how to import a certificate into the Trusted Root and Personal file certificate store, how to request a certificate signing request in Windows using Microsoft Management Console, and how to export a certificate in PFX format in Windows.

The absence of an SSL certificate implementation is causing this error, preventing successful connection to the domain controller through the LDP. Once implemented correctly, you will have the capability to establish an SSL connection to the domain controller. For guides on resolving some windows issues please check these: How to fix the issue “The remote session was disconnected because there are no Remote Desktop License Servers available to provide a license” and how to fix the issue “The Security Database on the Server does not have a Computer Account for this Workstation Trust Relationship” on Windows Server [Part 2], and how to quickly Fix Windows Search Bar Not Working.

Troubleshooting LDAP Connection

Without the SSL implementation, you will encounter the following outcome. In the next steps, I will be referring you to a solution that will help fix this LDAP connection error. Here is an interesting guide for you “Laps in Windows: How to Reset Directory Services Restore Mode (DSRM) Password“.

fix LDAP connection error

Resolving the Connection Error

In order to resolve this issue, kindly refer to this guide. If you are using a self-signed certificate, you will need to set up Active Directory Certificate Services. To completely fix this issue, read “How to generate a self-signed SSL certificate bound to an IP address“.

After installing the certificate, when next you try to bound the SSL with the IP address on the Ldp page as shown below, the error will be fixed.

preparing test connection - selecting SSL

The presence of an existing SSL certificate in LDP enables a successful connection to the domain controller. Now test the Ldp connection again and you should be able to connect now as shown below.

testing ldp connection - fix LDAP connection error

If this solution isn’t sufficient, review the Windows Event Log for additional error details. Launch the Windows Event Viewer and navigate to the following session.

Event Viewer 
- System Log

I hope you found this blog post on How to fix LDAP connection error helpful. If you have any questions, please let me know in the comment session.

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