ช่วยดูโค้ดส่งเมลล์ให้หน่อยครับ ทำไมส่งเมลล์ไม่ได้ครับ

if((move_uploaded_file($_FILES["filePO"]["tmp_name"],"myfile/".$_FILES["filePO"]["name"])&&(move_uploaded_file($_FILES["filePP"]["tmp_name"],"myfile/".$_FILES["filePP"]["name"]))))
	{
        $sql_in = " insert into datamain (job_no,supname , sup_tax, address, tel, email_sup , b_invoice , b_po , b_pp , invoice_no , po_no , pp_no , att_name , email_att , date_in , date_delivery, desciption  , price_unit ,quantity, a_price , weight , packaging ,  total_price , total_weight ,active) values ('$job','$supname', '$suptax ', '$address', '$tel' ,'$email_sup', '".$_FILES["fileIN"]["name"]."' , '".$_FILES["filePO"]["name"]."' , '".$_FILES["filePP"]["name"]."', '$invoice' , '$po' , '$pp' ,'$att_n' , '$email_att' , NOW(), '$date_del', '$des', '$p_u','$qty',  '$a_p', '$weight','$pack','$total_p','$total_w', 'wait') ";
	    $sql_q = mysql_query($sql_in);
		
		$strTo = $_POST['email_att'];
		$strSubject = "Activate Order";
		$strHeader = "Content-type: text/html; charset=UTF-8\n";
		$strHeader .= "From: [email protected]\nReply-To: [email protected]";
		$strMessage = "";
		$strMessage .= "Hello : ".$att_n."<br>";
		$strMessage .= "=================================<br>";
		$strMessage .= "Activate account click here.<br>";
		$strMessage .= "http://www.e-localsystem.com";
		$strMessage .= "=================================<br>";
		$strMessage .= "ThaiCreate.Com<br>";
		
		@mail($strTo,$strSubject,$strMessage,$strHeader); 
		echo "<script language=\"javascript\" type=\"text/javascript\"> alert('Complete') </script>";
		echo "<meta http-equiv='refresh' content='0; url=vender.php'>" ;
	}