title: Not receiving telegram notification from zabbix
body: <p>I have been using Zabbix for a while now. I tried to configure the telegram media type so as to receive notifications. Due to some error, I'm not receiving any notification. While testing the media type this is the error that appears on the log. Please help me resolve this.</p>
  <p><strong>Media type test log
  00:00:00.000 [Debug] [Telegram Webhook] URL: <a href="https://api.telegram.org/bot" rel="nofollow noreferrer">https://api.telegram.org/bot</a>/sendMessage
  00:00:00.000 [Debug] [Telegram Webhook] params: {&quot;chat_id&quot;:&quot;-xyxyxyxyxy&quot;,&quot;text&quot;:&quot;{ALERT.SUBJECT}\n{ALERT.MESSAGE}&quot;,&quot;disable_web_page_preview&quot;:true,&quot;disable_notification&quot;:false}
  00:00:05.183 [Debug] [Telegram Webhook] HTTP code: 200
  00:00:05.184 [Debug] [Telegram Webhook] notification failed: TypeError: cannot read property 'ok' of null</strong></p>