Why do I receive License Manager Error -96?

Why do I receive the following error? 

License checkout failed. Server node is down or not responding. License Manager Error -96

Answer 1

[MathWorks Support Team]

This error message indicates that there is a problem resolving the hostname of the license server. The license server hostname can be found in the SERVER line of the $MATLAB/licenses/network.lic file on your machine. The hostname must be resolvable for MATLAB to connect to it. 

This article will provide information on:

• How to test the Hostname Resolution
• What to do if the ping fails
• What to do if the ping is successful 

Test Hostname Resolution

Note: If you are working remotely and your organization requires a VPN, please ensure you are connected to the VPN, then attempt to start MATLAB before continuing.

To test the hostname, we need to use the ping application, which is a command line utility:

• On Windows, press the Windows key to invoke a global search, and then type in "cmd" to open Command Prompt.
• On macOS, launch the application "Terminal.app," located in the /Applications/Utilities folder.
• On Linux distributions, launch Terminal.

After launching the command line interface, enter this command:

ping <hostname> 

where <hostname> is the hostname of the license server as it appears on the SERVER line of your license file. The license file is named network.lic and is found under $MATLAB/licenses where $MATLAB is your root MATLAB installation directory.

If the output of the above command comes back as 'unreachable' or 'unresolvable', then proceed to the Ping Failed section below.  If the ping is successful and you are still unable to connect, proceed to the Ping Successful section below. 

Ping Failed

1) The best way to resolve the network connection issue is to contact your System Administrator.

2) Alternatively, if you are unable to resolve the hostname of the license server, but can ping the IP Address of the license server, you can replace hostname in the SERVER line of your local license with the IP Address of the license server. To do so:

1. Navigate to $MATLAB/licenses on your machine.
2. Open network.lic in a text editor e.g. Notepad, Notepad++
3. In the SERVER line, the second item is the hostname. Replace this with the IP address.
4. Save the file and launch MATLAB to test if MATLAB was able to connect to the license server.

NOTE: If your license server does not have a static IP, then this workaround will stop working when the DHCP lease is updated. You should contact your license administrator to try and resolve the issue with hostname resolution if your license server does not have a static IP.

Ping Successful 

If MATLAB is still unable to connect to the license server even though you can ping it successfully, there may be one or more firewalls blocking the connection between the MATLAB client and the MATLAB license server. The network license manager communicates on two ports that must be opened through the firewalls. If there is a firewall running, contact your System Administrator to open the necessary ports in the firewall.

For more information about the port the license manager uses, see the following article:

What ports does the Network License Manager use, and how can I set those ports?

For more information about checking your ports:

How can I check if the ports between Network License Manager and client are blocked?