Notification template is not reflecting in slack channel alerts

I have a channel to alert production servers uptime , and I have created a notification template and use that to the corresponding contact point (slack) for the alert but the template is not getting reflected.
I have used the same template and redirected the alerts to my test channel , that is working , to my this specific channel the template is not being formatted and still getting alerts in default template.

Check the channel allows incoming webhook messages and that there are no restrictions that might prevent the template from being applied. Check this once