Error sending data from Arduino to Matlab

I am trying to send temperature sensor data from arduino to matlab using serial communication. The temperature data are displayed on the Arduino serial monitor but I couldn't get the data in Matlab. The following error occurs. I've tried every possible ways to get the data by putting a pause(3) before fscanf but it still doesn't work.

Warning: Unsuccessful read: A timeout occurred before the Terminator was reached. 'serial' unable to read any data. For more information on possible reasons, see Serial Read Warnings. NaN

if ~isempty(instrfind)
    fclose(instrfind);
    delete (instrfind);
end

waitTime = 10;

s = serial('COM4','BAUD',9600);

waitTime = duration(0,waitTime,0);
t = datetime('now') - startTime;

while t < waitTime
    fopen(s);
    pause(3);
    idn = fscanf(s);
    fclose(s);

    serialData = str2double(idn);
    corrData = serialData;
    disp(corrData);
end


clear a;
clear s;