Redash_server: ERROR (abnormal termination)



UI stopped responding, shows empty page after login. I restarted all services with sudo supervisorctl restart all.
Got: redash_server: ERROR (abnormal termination)
Checked logs under /opt/redash/logs/supervisord.log:
2018-02-25 08:42:05,565 INFO exited: redash_server (exit status 255; not expected)
2018-02-25 08:42:06,565 INFO gave up: redash_server entered FATAL state, too many start retries too quickly

And not I’m getting 502 Bad Gateway instead of empty screen

Please assist