Fatal error: Uncaught MongoDB\Driver\Exception\ConnectionTimeoutException: No suitable servers found (`serverSelectionTryOnce` set): [connection refused calling hello on 'localhost:27017'] in /data/classroom_stg/english-classroom/public_html/classroom/vendor/mongodb/mongodb/src/functions.php:520 Stack trace: #0 /data/classroom_stg/english-classroom/public_html/classroom/vendor/mongodb/mongodb/src/functions.php(520): MongoDB\Driver\Manager->selectServer(Object(MongoDB\Driver\ReadPreference)) #1 /data/classroom_stg/english-classroom/public_html/classroom/vendor/mongodb/mongodb/src/Collection.php(687): MongoDB\select_server(Object(MongoDB\Driver\Manager), Array) #2 /data/classroom_stg/english-classroom/public_html/classroom/vendor/alcaeus/mongo-php-adapter/lib/Mongo/MongoCollection.php(562): MongoDB\Collection->findOne(Array, Array) #3 /data/classroom_stg/english-classroom/public_html/classroom/vendor/perftools/xhgui-collector/src/Xhgui/Saver.php(46): MongoCollection->findOne() #4 /data/classroom_stg/english-classroom/public in /data/classroom_stg/english-classroom/public_html/classroom/vendor/alcaeus/mongo-php-adapter/lib/Alcaeus/MongoDbAdapter/ExceptionConverter.php on line 85