Why is my website often put in maintenance mode by itself? My website in maintenance mode by itself. But other sites is work well, only this site has this problem. Some people encountered this kind of situation? Thank for help..
Usually, a Drupal site enters in maintenance mode by itself because is having problems to access to its database or when is set on that mode through the option located at "admin/config/development/maintenance".

If you are not able to log in on the site, that could indicate Db problems.

Check...:


at "admin/config/development/maintenance" is checked the option "Put site into maintenance mode". Or with drush: drush vget maintenance_mode 
the settings.php if the Drupal database parameters are ok.
the status of the Drupal database, (if the user:password are correct, if the database server is online).
the error logs (MySQL, PHP, Drupal).