@freeross in your first post, you did not mention you are getting the error while using VSCode. this is an important detail. I am not sure if it is relevant this time, but give us details of which extension is this you are getting the error.
anyways, “timeout” and “connection closed” are two distinct errors. the first one means there is no network toward the target. the second is, your case, from possibly a missing flag or something like that such that you connect but are not allowed to access.
the above is also true when you have a strict access setting in the “network settings” section. unless you have a static IP contract with your internet provider, your home modem or phone hotspot will have a different IP address anytime they are restarted. thus your connection to the database server will just be dropped.
go to your Atlas cluster and allow access from anywhere, “0.0.0.0”, to test if you can connect to the cluster that way.
PS: you have a static “name” to your cluster, but load balancing, primary changing, etc causes the IP change.