Warning: Unsuccessful read: A timeout occurred before the Terminator was reached. 'serial' unable to read any data

Hello!

I am trying to read data from Arduino uno but get this error

"Warning: Unsuccessful read: A timeout occurred before the Terminator was reached. 'serial' unable to read any data".

Can anyone help me please?

Thank you in advance!

clear All
close All

COM  = serial('COM2','BaudRate',9600);%5,'Terminator','CR');
set(COM,'TimeOut',10)
fopen(COM);
interv = 240;
init_time = 1;
x =0;
while (init_time < interv)
 b = fscanf(COM) ;
 b = b(2:end-2);
 b = bin2dec(b);
 x = [x,b];
 plot(x);
 grid on ;
 init_time = init_time+1;
 drawnow;
end
fclose(COM);
delete(COM);
clear COM;