NodeJS mongo client cannot resolve DNS name

Question

NodeJS v5.7.0 is with mongodb driver 2.1.2 used on CentOS6. Many times I get the following error trying to boot my nodejs server:

[2016-03-05 17:33:01.355] [INFO] [default] - TestGM online
Connecting to DB...

/home/beryllium/sitesrv/node_modules/mongodb/lib/mongo_client.js:415
          throw err
          ^
AssertionError: null == { [MongoError: getaddrinfo ENOTFOUND XXX.com XXX.com:27017]
  name: 'MongoError',
  message: 'ge
    at /home/beryllium/sitesrv/server.js:53:10
    at /home/beryllium/sitesrv/node_modules/mongodb/lib/mongo_client.js:412:11
    at _combinedTickCallback (node.js:370:9)
    at process._tickCallback (node.js:401:11)
[beryllium@njs sitesrv]$ 

where XXX.com runs MongoDB v3.2.

The nslookup and curl have no problems resolving IP for XXX.com.

What can be a problem?

EDIT

When I connect from the same machine/account where nodejs runs with mongo shell to the same server as Node cannot connect to, there is no problem:

mongo -u ZZZZ -p YYYY XXX.com/logs
MongoDB shell version: 3.2.3
connecting to: XXX.com/logs
Server has startup warnings: 
...
...