title: Error 400 bad request while sending message with Telegram Bot
body: <p>I have a Telegram Bot for a company employees which allows admin send messages to all employees (more than 10k users). List of all employees chat_id are stored in database and by using a specific command admin can send a message to all users.</p>
  
  <p>The problem is when the admin send a message to all employees it will be sent to some users (very first users in the loop on all users) but it will face error 400 (Bad request) for other users (errors are being logged in file).</p>
  
  <p>I'm using C# Webrequest object and I divide user list to pages of 100 user. After sending message to 100 user it goes to next 100 users.</p>
  
  <p>Can anyone help me with this ? 
  In general, is  this a good way to send bulk messages with telegram bot ?</p>