Graylog is restarting... There is no Graylog web application running at the moment, please reload this page in a minute. It can take up to 1-2 minutes until all services are running properly. In case this is a permanent error, check the following: Check if all services are running - sudo graylog-ctl status shows an overview of all running services Check for errors in log files - Relevant services write log files here: /var/log/graylog/*/current Ask for help - If there is no way to fix the issue ask for help: I got this error on my Gray-log server, upon troubleshooting I found that the disk was 100% full and was unable to start elastic search mongodb and etcd while checking gray-log server status with command #graylog-ctl status Solution to this problem was obvious that I have to clean some disk space to get gray-log working again but what file should I delete was my next thought! Upon googling I found that I could safely delete the old log files of elastic search to free ...