Embedded Coder: Why do I get a "model does not compile error" when trying to set the model interface?

Hi,

I'd like to modify the function specification for a Simulink model with Embedded Coder. I try to get the default configuration in the Model Interface view (Configuration Parameters -> Code Generation -> Interface -> Code interface -> Configure Model Functions). According to the text next to the button this invokes an "update diagram". I get the following bland error message:

"Model does not compile. The error message is: Error due to multiple causes." I do not see any verbose output in the MATLAB command window. Can you help here?

Updating the diagram manully (Ctrl+D) does not lead to an error.

Kind regards, Matthias