Try waiting a few minutes and reloading.
(Cannot access the database)
Backtrace:
#0 /home/sites/site100023424/web/nuclear-heritage.net/includes/libs/rdbms/loadbalancer/LoadBalancer.php(934): Wikimedia\Rdbms\LoadBalancer->reportConnectionError() #1 /home/sites/site100023424/web/nuclear-heritage.net/includes/libs/rdbms/loadbalancer/LoadBalancer.php(901): Wikimedia\Rdbms\LoadBalancer->getServerConnection() #2 /home/sites/site100023424/web/nuclear-heritage.net/includes/libs/rdbms/loadbalancer/LoadBalancer.php(1046): Wikimedia\Rdbms\LoadBalancer->getConnection() #3 /home/sites/site100023424/web/nuclear-heritage.net/includes/GlobalFunctions.php(2469): Wikimedia\Rdbms\LoadBalancer->getMaintenanceConnectionRef() #4 /home/sites/site100023424/web/nuclear-heritage.net/includes/cache/localisation/LCStoreDB.php(56): wfGetDB() #5 /home/sites/site100023424/web/nuclear-heritage.net/includes/cache/localisation/LocalisationCache.php(449): LCStoreDB->get() #6 /home/sites/site100023424/web/nuclear-heritage.net/includes/cache/localisation/LocalisationCache.php(495): LocalisationCache->isExpired() #7 /home/sites/site100023424/web/nuclear-heritage.net/includes/cache/localisation/LocalisationCache.php(371): LocalisationCache->initLanguage() #8 /home/sites/site100023424/web/nuclear-heritage.net/includes/cache/localisation/LocalisationCache.php(312): LocalisationCache->loadItem() #9 /home/sites/site100023424/web/nuclear-heritage.net/languages/Language.php(3223): LocalisationCache->getItem() #10 /home/sites/site100023424/web/nuclear-heritage.net/includes/specialpage/SpecialPageFactory.php(361): Language->getSpecialPageAliases() #11 /home/sites/site100023424/web/nuclear-heritage.net/includes/specialpage/SpecialPageFactory.php(420): MediaWiki\SpecialPage\SpecialPageFactory->getAliasList() #12 /home/sites/site100023424/web/nuclear-heritage.net/includes/Title.php(1255): MediaWiki\SpecialPage\SpecialPageFactory->resolveAlias() #13 /home/sites/site100023424/web/nuclear-heritage.net/includes/MediaWiki.php(200): Title->isSpecial() #14 /home/sites/site100023424/web/nuclear-heritage.net/includes/MediaWiki.php(940): MediaWiki->performRequest() #15 /home/sites/site100023424/web/nuclear-heritage.net/includes/MediaWiki.php(543): MediaWiki->main() #16 /home/sites/site100023424/web/nuclear-heritage.net/index.php(53): MediaWiki->run() #17 /home/sites/site100023424/web/nuclear-heritage.net/index.php(46): wfIndexMain() #18 {main}