I am using debian 9
After enter this command sudo systemctl start mongod.service it shows:

 Failed to connect to bus: No such file or directory 

But This command is working:

sudo systemctl enable mongod 

How to solve this problem?

And After entering this command mongo --eval 'db.runCommand({ connectionStatus: 1 })' it shows:

MongoDB shell version v4.0.17
connecting to: mongodb://
2020-03-27T01:42:18.705+0530 E QUERY    [js] Error: couldn't connect to server, connection attempt failed: SocketException: Error connecting to :: caused by :: Connection refused :
exception: connect failed
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  • Debian 9 is neither Xubuntu. Lubuntu or or flavor of Ubuntu, thus off-topic on this site. Refer askubuntu.com/help/on-topic for site rules, and also alternate SE sites where you question will be on-topic. – guiverc Mar 26 at 22:50

Type not sudo systemctl start mongod.service but sudo systemctl start mongodb.service. Maybe in the second command it autocompletes command to mongodb.service.

You've inputed the service name incorrectly. But to check, what is its name, use

systemctl list-units --type=service | grep mongo

During installation on Ubuntu 19.10 apt says:

Created symlink /etc/systemd/system/multi-user.target.wants/mongodb.service → /lib/systemd/system/mongodb.service.

Your command also shows correct output:

$ mongo --eval 'db.runCommand({ connectionStatus: 1})'
MongoDB shell version v3.6.8
connecting to: mongodb://
Implicit session: session { "id" : UUID("88af9e26-ed2f-4fe7-a898-b921acdc5652") }
MongoDB server version: 3.6.8
    "authInfo" : {
        "authenticatedUsers" : [ ],
        "authenticatedUserRoles" : [ ]
    "ok" : 1

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