Ubuntu server 20.04 installation - mongodb problems?

I installed Rocket.Chat on Ubuntu 20.04 server.
Followed the official guide: Rocket.Chat in Ubuntu - Rocket.Chat Docs

I have a problem with running. Something bad with mongod.

systemctl status mongod.service
● mongod.service - MongoDB Database Server
Loaded: loaded (/lib/systemd/system/mongod.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Tue 2021-02-09 20:42:17 UTC; 3min 12s ago
Docs: https://docs.mongodb.org/manual
Process: 15141 ExecStart=/usr/bin/mongod --config /etc/mongod.conf (code=exited, status=100)
Main PID: 15141 (code=exited, status=100)

Feb 09 20:42:16 teamspeak systemd[1]: Started MongoDB Database Server.
Feb 09 20:42:17 teamspeak systemd[1]: mongod.service: Main process exited, code=exited, status=100/n/a
Feb 09 20:42:17 teamspeak systemd[1]: mongod.service: Failed with result ‘exit-code’.

Server Setup Information

  • Version of Rocket.Chat Server: latest
  • Operating System: Ubuntu 20.04 server
  • Deployment Method: tar
  • Number of Running Instances: 1
  • DB Replicaset Oplog:
  • NodeJS Version: 12.18.4
  • MongoDB Version: 4.0.22
  • Proxy: apache
  • Firewalls involved: fw inactive

If I run mongo --eval ‘db.runCommand({ connectionStatus: 1 })’
MongoDB shell version v4.0.22
connecting to: mongodb://
2021-02-09T20:49:25.116+0000 E QUERY [js] Error: couldn’t connect to server, connection attempt failed: SocketException: Error connecting to :: caused by :: Connection refused :
exception: connect failed

thank you