How to read UDP data into a vector/array in MATLAB App Designer?

I can't seem to read UDP data into a vector/array in App Designer. I can send a vector/array successfully and receive one in the command window if I try, but not from App Designer. I don't get any errors, it just doesn't work. Here is the code I am currently trying:

function ReadData(app) % read data from UDP values_recieved = fscanf(app.u); app.Recieve_values = str2double(values_recieved);

            % update sensor values array
            app.Recieve_values_array = [app.Recieve_values_array(2 : end); app.Recieve_values];

            % update Speed and Torque gauge with the latest values
            app.SpeedRPMGauge.Value = app.Recieve_values(4);
            app.EditFieldSpeedLabel.Value = app.Recieve_values(4);
            app.TorqueNmGauge.Value = app.Recieve_values(3);
            app.EditFieldTorqueLabel.Value = app.Recieve_values(3);

            % plot Torque sensor value vs Speed sensor value in GUI
            % area(app.UIAxes, app.Recieve_values(4), app.Recieve_values(4), 'LineWidth', 2); 
        end

[Tyler Kirsten]

I changed the line: app.Recieve_values = str2double(values_recieved); to: app.Recieve_values = str2num(values_recieved); and it worked for perfectly for a while, then without changing anything it started giving me the same error again "Index exceeds matrix dimensions" and basically freezes the app.

Any ideas?