Understanding Heroku server status 143

Exit code 143 means that your process was terminated by a SIGTERM. This is generally sent when you do any commands that require your dynos to restart (config:set, restart, scale down...).

Daily restarts is a regularly Heroku dynos lifecycle activity:

Heroku automatic dyno restarts

It is an idle state when it does not receive any request for a while. When it receives a request it will start again.

It is due to the heroku app stopped by dyno. So you have to restrat the app. You can type heroku restart in the terminal. Also heroku restart --app application_name