How to post images to mysql using unity webrequest?

Hello i need your help, I am trying to post image data in form of Base64string to a php script. It is working on my localhost in right way.But when i am using same logics for my web server, It only works when i am posting the small size images but not working when i am posting large size images. And even if small images are posted my webrequest with async operation keeps on overlooping and never return isDone ==true. Here is my c# code

public void upload() {

    Sprite sp = GetComponent<Image>().sprite;
     byte[] bytes = sp.texture.EncodeToPNG();
     string imgstr = Convert.ToBase64String(bytes);

     WWWForm insertInfo = new WWWForm();

      insertInfo.AddField("servername", dbcon.Server_name1);
      insertInfo.AddField("username", dbcon.Username1);
      insertInfo.AddField("password", dbcon.Password1);
      insertInfo.AddField("database_name", dbcon.Database_name1);

     insertInfo.AddField("data_value", "Anyone");
     insertInfo.AddField("img_value", imgstr);
     insertInfo.AddField("data_column_name", "actual_data");  
     insertInfo.AddField("image_column_name", "data_img");
     insertInfo.AddField("table_name", "sft_table");

 tryagain: using (UnityWebRequest dataInserturl = UnityWebRequest.Post("https://myserver.com/myphpfolder/Insertinformation.php", insertInfo))
     {

          UnityWebRequestAsyncOperation web_Async_Operation = dataInserturl.SendWebRequest();
         if (dataInserturl.isNetworkError || dataInserturl.isHttpError)
         {
             Debug.LogError("Insert B Error-" + dataInserturl.error);
             yield return new WaitForEndOfFrame();
             //  goto tryagain;
         }
         while (!web_Async_Operation.isDone)
         {
             Debug.Log("Progress=" + web_Async_Operation.progress);  
             yield return new WaitForFixedUpdate();
         }
         rawtext0 = dataInserturl.downloadHandler.text.Trim();
         Debug.LogError("Rawtext=" + rawtext0);
                 }

Here is my php Code

Thank you people in advance, if you have any solution or a better idea to perform such operation than please post your solutions.