Why do I receive a Connector error with last error "Address already in use" when launching MATLAB or Simulink?

Why do I receive the following error when starting MATLAB?

Warning: Issue starting Connector. Please check that port 31415 is available. Did not start the server. Desired port was: 31515.

Last error was: Error while starting socket: Net Exception: Address already in use: 127.0.0.1:31714, 10048

Or the following error when starting Simulink? ERROR: Warning: Error in Connector: Did not start the server. Desired port was: 31515. Last error was: Error while starting socket: Net Exception: Address already in use: 127.0.0.1:31714, 10048

Answer 1

[MathWorks Support Team]

This issue is related to the fact that MATLAB tries to bind to all loopback network interfaces found on the system. If there are more than one network interface, it could be causing a conflict which results in the Connector Errors. Removing any loopback network interfaces such as Wireshark & Npcap should resolve the issue.

Answer 2

[Abiola Olaleye]

Solution

To add a Windows firewall port exception:

1. On the client operating system, go to Start>Run and type firewall.cpl. The Windows Firewall window opens.
2. Click on the “Advanced Settings” link on the left pane. The Windows Firewall with Advanced security window opens.
3. Click on the “Inbound Rules” option.
4. On the left pane, click on “New rule”.
5. Under “Rule Type” select the option “Port” and click next.
6. Select “TCP”and “specific local ports” options.
7. Key in the port number, the default port is TCP port 135.
8. Click Next.
9. Select the option “Allow the connection”.
10. Click Next, do not change any option here and click Next again.
11. Specify a name for this rule.
12. Click Finish.

[Ridhima Chopra]

Thank you so much!! It really solved my problem!!