The class atlas cluster consists of three different nodes and you must be able to make outgoing requests to all these three nodes.
cluster0-shard-00-00-jxeqq.mongodb.net
cluster0-shard-00-01-jxeqq.mongodb.net
cluster0-shard-00-02-jxeqq.mongodb.net
Hope it helps!
Thanks,
Shubham Ranjan
Curriculum Services Engineer