Why do I get the "ERR_CONNECT_FAIL" error when opening Simulink Start Page or Simulation Data Inspector?

When attempting to open a Simulink-related UI, mostly either the Simulink Start Page or the Simulation Data Inspector (SDI), it opens a new window but displays an error message.

The error message shows either of the following error messages, or both.

503 Service Unavailable

ERR_CONNECT_FAIL

Answer 1

[MathWorks Support Team]

A possible solution to this is to change the network configuration options on the machine such that it is able to establish a loopback connection by opening and closing ports and communicating through the localhost. In some situations, users' configuration may block or have some form of proxy that reroutes localhost traffic. In these situations, the connector may fail to communicate properly.

On Windows 7 and 10, navigate to Internet Explorer (or Control Panel -> Network settings) -> Internet Options -> Connections -> LAN Settings -> turn ON "Bypass proxy server for local addresses", with "Use a proxy server for you LAN" most likely already ON.

On Mac OS X, navigate to System Preferences -> Network -> Advanced -> Proxies -> turn ON "Exclude simple hostnames".

Note:

You can run the following command in the MATLAB Command Window to open Simulink Library Browser without opening the Simulink Start Page.

>> slLibraryBrowser