I am trying to open configuration > sales > payment methods but it shows
Service Unavailable The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
Apache/2.4.29 (Ubuntu) Server at mysitename.de Port 80
i have tried with this
php bin/magento maintenance:disable php bin/magento cache:flush
and there is also no any .maintenance.flag in root or in var directory
how to fix it in magento 2