Your connect string is not correct
You must have taken it from your lecture
It is just an example xxxx is just a place holder
You have to use your own cluster name
Where can I find my cluster name? or you are referring to the link I used for connection?
Have you created your Sandbox cluster?
If yes follow steps from
Chapter 2 : Connecting to Your Sandbox Cluster from the mongo Shell
Please check our forum threads
I hope you found @Ramachandra_37567’s response helpful.
The instruction for getting the connection string of an
Atlas cluster is mentioned in this lecture : Chapter 2 : Connecting to Your Sandbox Cluster from the mongo Shell.
Let us know if you are still having any confusions.