x509: certificate signed by unknown authority

[rtzra]

Describe the bug
Although I set Telegram channel webhook address in config.yaml file, I didn't get any notifications.

Actual behavior
My config:

data:
  config.yaml: |
    maxRecentLogLines: 10
    ignoreFailedGracefulShutdown: true
    alert:
      telegram:
          token: XXX
          chatId: -YYY

Error in pod logs:

level=error msg="failed to send event with Telegram: Post "https://api.telegram.org/botXXX/sendMessage\": x509: certificate signed by unknown authority"

Expected behavior
Should get kwatch notification to my Telegram channel.

Version/Commit
A version or commit of kwatch: 0.5.0
I'm run kwatch in k8s (1.17), as described in manual.