What should I do? It echo data insert but the database is blank no data insert

Notice: Undefined index: datepicker in C:\xampp\htdocs\psm1\studRequest1.php on line 5

Notice: Undefined index: message in C:\xampp\htdocs\psm1\studRequest1.php on line 6
Error : INSERT INTO booking (datepicker,message) VALUES ('','')

  1  This is my html file
  2  
  3   <form class="modal-content animate" action="studRequest1.php"> 
  4              <div class="imgcontainer"> 
  5                  <span onclick="document.getElementById('id01').style.display='none'" class="close" title="Close Modal">×</span> 
  6                  
  7              </div> 
  8    				
  9              <div class="container"> 
 10                  
 11  				<label for="datepicker">Date for Appointment</label><br>
 12  				<input type="text" id="datepicker" name="datepicker" width="30%" autocomplete="off" placeholder="Select Date Here" >
 13  				
 14  				<br>
 15                  <label for="message">Message</label> <br>
 16  				<textarea rows="4" cols="50" type="message" id="message" placeholder="" name="message" required> </textarea>
 17  				
 18  				<button type="submit" class="btn btn-primary" name="submit" value="submit">Submit</button>
 19                    
 20              </div> 
 21    
 22              <div class="container" style="background-color:#f1f1f1"> 
 23                  <button type="button" onclick="document.getElementById('id01').style.display='none'" class="cancelbtn">Cancel</button> 
 24              </div> 
 25          </form> 

  1  <?php 
  2  
  3  session_start();
  4  	include ('connection.php');
  5  	$datepicker = $_POST['datepicker'];
  6  	$message = $_POST['message'];
  7  	
  8  	$sql="INSERT INTO booking (datepicker,message)
  9  	VALUES ('$datepicker','$message')";
 10  	
 11  
 12  							$resultInsert = mysqli_query($conn, $sql) or die(mysqli_error($sql));
 13  
 14  							if($resultInsert === TRUE)
 15  		{
 16  			echo"<script>alert('Data Insert');</script>";
 17     //          echo "<script>window.location.assign('studAppointment.php')</script>";
 18  		}
 19  		{
 20  					
 21  				echo "Error : ". $sql . "<br>" . $conn -> error;
 22  					}
 23  
 24  	
 25  ?>