Problem with update from 2.9.4 to 2.9.5

What does it means and what can i do:

Fatal error: Uncaught exception Exception with message Could not connect to database (Access denied for user 'root'@'localhost' (using password: NO)) thrown in /home/........................./public_html/system/libraries/Database.php on line 78

#0 /public_html/system/libraries/Database.php(136): Database->__construct()
#1 /public_html/system/libraries/System.php(147): Database::getInstance()
#2/public_html/system/libraries/Model.php(86): System->import(Array)
#3 /public_html/system/modules/backend/BackendUser.php(73): Model->__construct('Database')
#4 /public_html/system/modules/backend/BackendUser.php(158): BackendUser->__construct()
#5 /public_html/system/libraries/System.php(147): BackendUser::getInstance()
#6 /public_html/contao/index.php(61): System->import()
#7 /public_html/contao/index.php(145): Index->__construct(Array)
#8 {main}

It means it can't connect to your database.

You did a manual update, I take it? You likely overwrote "/system/config/localconfig.php" which contained all of your site's settings.

Try running the install tool -- "/contao/install.php" -- and fill out everything again, including your database connection info.

ok