CiviCRM includes a few places in the user-interface that display blurbs or messages from civicrm.org. This backend application hosts those messages. It's based on Symfony Standard Edition (~2.2).

Content authors see: Editing and updating messages

If you've already configured buildkit, then:

## Add hostname, e.g. "127.0.0.1 messages.local"
$ vi /etc/hosts

## Download and install
$ civibuild create messages --url http://messages.local

## Restart Apache

git clone https://github.com/civicrm/civicrm-community-messages.git
cd civicrm-community-messages
cp app/config/parameters.yml.dist app/config/parameters.yml
vi app/config/parameters.yml
composer install
./app/console doctrine:schema:create

Then setup your http server (per preference).

By default, CiviCRM pulls messages from https://alert.civicrm.org. To display messages from your own installation, put this in civicrm.settings.php:

$civicrm_setting['CiviCRM Preferences']['communityMessagesUrl']
 = 'http://messages.local/alert?prot=1&ver={ver}&uf={uf}&sid={sid}&lang={lang}&co={co}';

Check the error log on www-prod:

tail -f /var/log/nginx/alert.error.log

Try clearing the symphony app cache:

sudo -i -u commsg
cd /var/www/alert.civicrm.org/app
./console cache:clear -e prod