Not able to insert value to the database

Ionic Framework ionic-v3
1

I want to insert value to the database
.ts

submitData() {
    let datatopost:any = {};
    if(this.MySelect1.length >0) {
      for(let i=0; i<=this.MySelect1.length; i++) {
        datatopost = {"name":this.doc_name[i],"address":this.doc_add[i],"contact":this.doc_cont[i]};
        this.post_to_server.push(datatopost);
      }
      console.log("Final Data...");
         this.http.post("http://www.mydomain.com/test/append/includes/classes/multiplefield/insert.php",JSON.stringify(this.post_to_server))
      .subscribe(data => {
       let temData =data.json()
        let response = temData.code;

      }, error => {
        
        // Error getting the data
        console.log(error);
      });
  }
 }

below my php code .php

<?php include 'connection.php'; if($conn) 
{ 


$json = file_get_contents('php://input'); 
$obj = json_decode($json,true); 
foreach($obj as $key => $value) {
    echo $value->name;
 $query = 'insert into multiple_filed (send_time,send_location,send_comments) values('.$value->name.','. $value->address.','. $value->contact.')';
  mysqli_query($conn,$query); } }

  ?>

Showing an error like this Trying to get property of non-object
please help me out
Thanks