Try waiting a few minutes and reloading.
(Cannot access the database)
Backtrace:
#0 /usr/share/mediawiki/includes/libs/rdbms/loadbalancer/LoadBalancer.php(758): Wikimedia\Rdbms\LoadBalancer->reportConnectionError() #1 /usr/share/mediawiki/includes/page/WikiPage.php(495): Wikimedia\Rdbms\LoadBalancer->getConnection() #2 /usr/share/mediawiki/includes/page/WikiPage.php(608): WikiPage->loadPageData() #3 /usr/share/mediawiki/includes/page/WikiPage.php(649): WikiPage->exists() #4 /usr/share/mediawiki/includes/page/WikiPage.php(287): WikiPage->getContentModel() #5 /usr/share/mediawiki/includes/page/WikiPage.php(274): WikiPage->getContentHandler() #6 /usr/share/mediawiki/includes/actions/Action.php(98): WikiPage->getActionOverrides() #7 /usr/share/mediawiki/includes/actions/Action.php(155): Action::factory() #8 /usr/share/mediawiki/includes/MediaWiki.php(155): Action::getActionName() #9 /usr/share/mediawiki/includes/MediaWiki.php(782): MediaWiki->getAction() #10 /usr/share/mediawiki/includes/MediaWiki.php(515): MediaWiki->main() #11 /usr/share/mediawiki/index.php(42): MediaWiki->run() #12 {main}