Drupal already installed

Warning: file_get_contents(/var/www/www.mpm.edu/docroot/../salt.txt): failed to open stream: No such file or directory in /var/www/www.mpm.edu/vendor/acquia/blt/settings/blt.settings.php on line 106
Warning: file_get_contents(/var/www/www.mpm.edu/docroot/../salt.txt): failed to open stream: No such file or directory in require() (line 106 of /var/www/www.mpm.edu/vendor/acquia/blt/settings/blt.settings.php).

require('/var/www/www.mpm.edu/vendor/acquia/blt/settings/blt.settings.php') (Line: 766)
require('/var/www/www.mpm.edu/docroot/sites/default/settings.php') (Line: 122)
Drupal\Core\Site\Settings::initialize('/var/www/www.mpm.edu/docroot', 'sites/default', Object) (Line: 1029)
Drupal\Core\DrupalKernel->initializeSettings(Object) (Line: 270)
Drupal\Core\DrupalKernel::createFromRequest(Object, Object, 'install', 1) (Line: 412)
install_begin_request(Object, Array) (Line: 114)
install_drupal(Object) (Line: 44)

Drupal already installed | Drupal

Drupal already installed

To start over, you must empty your existing database and copy default.settings.php over settings.php.
To upgrade an existing installation, proceed to the update script.
View your existing site.