GraphVar error while attempting to perform a correlation

I'm not sure if this error has already been diagnosed on the forum. I couldn't find a thread refering to it.
This is the setup I'm using:

The error is the following:

Error using getMeanMatrix (line 79)
The field "cutmeansub1_a_rest1" has not been found:
Error in GraphVar_calc (line 93)
Error in GraphVar>Btn_calcCorr_Callback (line 73)
[res allTask] = GraphVar_calc(handles);
Error in gui_mainfcn (line 96)
Error in GraphVar (line 40)
    gui_mainfcn(gui_State, varargin{:});
Error in @(hObject,eventdata)GraphVar('Btn_calcCorr_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating uicontrol Callback


The variable "cutmeansub1_a_rest1" is stored in the first .mat file listed in the Subjects box.
This is probably a very simple mistake, but I'm new to the software, so any help will be welcomed.
Thank you!


the "Corr Matrix Array" within the subjet´s .mat files has to have the same naming across all subjects (e.g., CorrMatrix). Please have a look how this is organized in the sample subjects in the sample workspace (for me it look like you named this subject specific "cutmeansub1_a_rest1"