将mongodb 4.0与robomongo连接

Question

以下是我的mongodb状态的日志，其中显示了运行状态

ubuntu@ip-172-31-9-130:/etc$ sudo service mongod status
● mongod.service - MongoDB Database Server
   Loaded: loaded (/lib/systemd/system/mongod.service; disabled; vendor preset: 
   Active: active (running) since Fri 2018-09-28 09:50:43 UTC; 37min ago
     Docs: https://docs.mongodb.org/manual
 Main PID: 28315 (mongod)
   CGroup: /system.slice/mongod.service
           └─28315 /usr/bin/mongod --config /etc/mongod.conf

Sep 28 09:50:43 ip-172-31-9-130 systemd[1]: Started MongoDB Database Server.
Sep 28 09:50:43 ip-172-31-9-130 mongod[28315]: 2018-09-28T09:50:43.848+0000 I CO
lines 1-10/10 (END)

但是当我将其与robomongo连接时，会引发错误

Failed to connect to the server

请帮助！