Why do I get the error "Simulink engine interface is not enabled"?

Why do I get the error message "Simulink engine interface is not enabled"?

It may appear in different contexts, for example:

(1) By running the following script:

>> a=RTW.ModelSpecificCPrototype;
>> attachToModel(a,gcs)
>> getDefaultConf(a)
Error using RTW.ModelSpecificCPrototype/getDefaultConf (line 84)
Model does not compile. The error message is: Simulink engine interface is not enabled.

(2) When trying to convert a subsystem to a referenced model:

The subsystem 'untitled/Subsystem' cannot be converted to a referenced model.
Simulink engine interface is not enabled.

(3) When running HDL Code Advisor or HDL Workflow Advisor, the message appears during the Algebraic loop check:

Abnormal exit: Simulink engine interface is not enabled.

Answer 1

[MathWorks Support Team]

This error arises when a required network license key is unavailable. Most likely, this involves Coder products.

You can run the following commands to see whether you are able to check out licenses ('1' means successful checkout). Note that not all of the mentioned licenses may be required for your particular workflow.

>> license('checkout','matlab')             % MATLAB
>> license('checkout','Simulink')           % Simulink
>> license('checkout','Matlab_Coder')       % MATLAB Coder
>> license('checkout','Real-Time_Workshop') % Simulink Coder
>> license('checkout','RTW_Embedded_Coder') % Embedded Coder

If a command returns '0', it means the license is missing. In this case, contact your local MATLAB License Administrators for help.

Depending on the blocks used in your model, additional licenses may be required. Use the following function to find out about your model's dependencies:

https://www.mathworks.com/help/simulink/slref/dependencies.toolboxdependencyanalysis.html