Summary

The "No Server to Connect To" error indicates that GibbsCAM cannot establish communication with the Network License (NLO) server.

In most cases, the problem is caused by one of the following:

  • The client cannot communicate with the RLM license server.

  • The RLM service is not running.

  • The server name, IP address, or port is incorrect.

  • The server's license file does not support the version of GibbsCAM being launched.

This article explains how to identify and resolve each of these scenarios.

Table of Contents

Cause

This error indicates that the client workstation cannot communicate with the Network License (NLO) server or cannot obtain a compatible license from it.

Common causes include:

  • The RLM service is not running.

  • The server is offline.

  • The client is using an incorrect server name or IP address.

  • A firewall or security software is blocking communication.

  • The RLM ports are blocked.

  • The server license file does not support the version of GibbsCAM being launched.

Resolution

Follow the steps below in order.


Step 1 – Verify the License Server Is Running

On the license server:

  • Confirm the computer is powered on.

  • Verify that the RLM License Server service is running.


  • Open the RLM Web Administration page and confirm that the license server has loaded the GibbsCAM license successfully.

If the server is unavailable, restart the RLM service and test the client again.


Step 2 – Verify the Client Can Reach the Server

Confirm that the client is configured to connect to the correct server.

Verify:

  • Server hostname

  • IP address

  • Network connection

  • VPN connection (if applicable)

If necessary, test communication using PowerShell:

Test-NetConnection <ServerNameOrIPAddress> -Port 2764


Replace <ServerNameOrIPAddress> with the hostname or IP address of your license server.

A successful test indicates that the client can communicate with the RLM server port.


Step 3 – Check Firewall and Security Software

Ensure that Windows Firewall and any endpoint security software allow communication between the client and the license server.

Verify that the required RLM ports are open.

By default, GibbsCAM uses:

Service

Default Port

RLM License Server

2764


2765

RLM Web Administration

5054

If your organization uses custom ports, verify that both the server and client are configured consistently.


Step 4 – Verify the Server License Supports the Installed GibbsCAM Version

If communication succeeds but the error still occurs, verify that the server license file supports the version of GibbsCAM you are launching.

This issue commonly occurs after installing a newer GibbsCAM release without updating the server license.

For example:

  • The server license supports GibbsCAM 2025.

  • The client is running GibbsCAM 2026.

In this situation, the client cannot obtain a compatible license until the server license file has been updated.

Update the server license file and restart the RLM service.


Step 5 – Verify the Client License Configuration

If only one workstation experiences the problem:

  • Verify that it is configured to use the correct server.

  • Confirm that the server name and port are entered correctly.

  • Test another workstation to determine whether the issue is isolated to one computer.

Expected Result

The client successfully connects to the Network License Server, checks out a license, and GibbsCAM starts without displaying the "No Server to Connect To" error.

Troubleshooting

  • Problem: Every Client Displays the Error

Cause

The license server is unavailable or the RLM service is not running.

Resolution

Verify that the server is online, the RLM service is running, and the license file has loaded successfully.


  • Problem: Only One Client Displays the Error

Cause

The affected workstation cannot communicate with the server or is configured incorrectly.

Resolution

Verify the server name, IP address, firewall settings, and port configuration.


  • Problem: The Error Appeared After Installing a New GibbsCAM Version

Cause

The server license file does not support the newer GibbsCAM version.

Resolution

Update the server license file and restart the RLM service before launching the newer client.


  • Problem: The PowerShell Connection Test Fails

Cause

Communication to the RLM server is blocked.

Resolution

Verify network connectivity, firewall rules, VPN configuration (if applicable), and that the RLM service is listening on the expected ports.

Best Practices

  • Keep the RLM server license file current when upgrading GibbsCAM.

  • Verify network connectivity before troubleshooting licensing.

  • Document the server hostname, IP address, and configured ports.

  • Restart the RLM service after updating the server license.

  • Periodically verify client connectivity using the PowerShell test.

Keywords

No Server to Connect To, RLM, Network License, NLO, License Server, Cannot Connect, Client Connection, Firewall, Port 2764, Port 2765, Server License, RLM Service