Hello, I was trying to connect to the cluster by compass, but I was not connecting, so I decided to open the shell mongo and connect to the cluster, and it worked, right after that I tried to connect again by compass and this time connected!
Should you just connect to the cluster via compass when connected to the shell? or was it a bug / error?
There is no such thing that you need to be connected to your cluster from mongo shell before attempting a connection from Compass. There might be some other issue because of which you were not able to connect to your cluster from Compass in the first place.
If you have any other query please feel free to get back to us.
Happy Learning 
Thanks,
Shubham Ranjan
Curriculum Support Engineer