Thank you @Jason_Tran
This is the output of nslookup
nslookup -type=txt sandbox.rmjaa.mongodb.net
Server: dlinkrouter
Address: 192.168.0.1
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to dlinkrouter timed-out
An example of how to obtain this can be found here on this post although you’ll need to select connection via mongo shell rather than the node.js driver.
Upon selecting mongosh option, I get the same url (it has no mention of authSource and replicaSet)