MediaWiki internal error.

Original exception: [ad0b2ec1ce68e6f1d77991ff] /wiki/Kategorie:Wetten_%26_Tipps Error from line 657 of /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionHandler.php: Class 'FormatJson' not found
Backtrace:
#0 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionHandler.php(195): MWExceptionHandler::logError()
#1 /var/www/wettmaxx.com/shared/wiki/includes/AutoLoader.php(81): MWExceptionHandler::handleError()
#2 /var/www/wettmaxx.com/shared/wiki/includes/AutoLoader.php(81): require()
#3 [internal function]: AutoLoader::autoload()
#4 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionHandler.php(621): spl_autoload_call()
#5 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionHandler.php(111): MWExceptionHandler::logException()
#6 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionHandler.php(129): MWExceptionHandler::rollbackMasterChangesAndLog()
#7 /var/www/wettmaxx.com/shared/wiki/includes/MediaWiki.php(550): MWExceptionHandler::handleException()
#8 /var/www/wettmaxx.com/shared/wiki/index.php(43): MediaWiki->run()
#9 {main}

Exception caught inside exception handler: [ad0b2ec1ce68e6f1d77991ff] /wiki/Kategorie:Wetten_%26_Tipps Wikimedia\Rdbms\DBConnectionError from line 800 of /var/www/wettmaxx.com/shared/wiki/includes/libs/rdbms/database/Database.php: Cannot access the database: php_network_getaddresses: getaddrinfo failed: No address associated with hostname (proxy01)
Backtrace:
#0 /var/www/wettmaxx.com/shared/wiki/includes/libs/rdbms/loadbalancer/LoadBalancer.php(1028): Wikimedia\Rdbms\Database->reportConnectionError()
#1 /var/www/wettmaxx.com/shared/wiki/includes/libs/rdbms/loadbalancer/LoadBalancer.php(670): Wikimedia\Rdbms\LoadBalancer->reportConnectionError()
#2 /var/www/wettmaxx.com/shared/wiki/includes/GlobalFunctions.php(2858): Wikimedia\Rdbms\LoadBalancer->getConnection()
#3 /var/www/wettmaxx.com/shared/wiki/includes/cache/MessageCache.php(471): wfGetDB()
#4 /var/www/wettmaxx.com/shared/wiki/includes/cache/MessageCache.php(426): MessageCache->loadFromDB()
#5 /var/www/wettmaxx.com/shared/wiki/includes/cache/MessageCache.php(350): MessageCache->loadFromDBWithLock()
#6 /var/www/wettmaxx.com/shared/wiki/includes/cache/MessageCache.php(991): MessageCache->load()
#7 /var/www/wettmaxx.com/shared/wiki/includes/cache/MessageCache.php(919): MessageCache->getMsgFromNamespace()
#8 /var/www/wettmaxx.com/shared/wiki/includes/cache/MessageCache.php(888): MessageCache->getMessageForLang()
#9 /var/www/wettmaxx.com/shared/wiki/includes/cache/MessageCache.php(828): MessageCache->getMessageFromFallbackChain()
#10 /var/www/wettmaxx.com/shared/wiki/includes/Message.php(1275): MessageCache->get()
#11 /var/www/wettmaxx.com/shared/wiki/includes/Message.php(842): Message->fetchMessage()
#12 /var/www/wettmaxx.com/shared/wiki/includes/Message.php(934): Message->toString()
#13 /var/www/wettmaxx.com/shared/wiki/includes/OutputPage.php(950): Message->text()
#14 /var/www/wettmaxx.com/shared/wiki/includes/OutputPage.php(997): OutputPage->setHTMLTitle()
#15 /var/www/wettmaxx.com/shared/wiki/includes/OutputPage.php(2478): OutputPage->setPageTitle()
#16 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionRenderer.php(126): OutputPage->prepareErrorPage()
#17 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionRenderer.php(54): MWExceptionRenderer::reportHTML()
#18 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionHandler.php(75): MWExceptionRenderer::output()
#19 /var/www/wettmaxx.com/shared/wiki/includes/exception/MWExceptionHandler.php(130): MWExceptionHandler::report()
#20 [internal function]: MWExceptionHandler::handleException()
#21 {main}