Force close connections on mongo db that runs in atlas cloud

I have a mongo db cluster hosted on AWS via atlas cloud offering.Problem: I have gotten myself into a situation where I have idle/stale connections connected to my cluster and I can't seem to get rid of them.

The connection count is 98 and my tier allows be to have just 100.

I do have ability to connect to this cluster via Mongo Shell or other tooling, but I can't seem to find a way to restart the service or to force close the connections.

Now I do not have access to the underlying container or VM so I can't control control the mongo service.

When I connect through the shell I tried

db.runCommand( { killAllSessions: [ ] } )

but that gave me

{ "ok" : 0, "errmsg" : "CMD_NOT_ALLOWED: killAllSessions", "code" : 8000, "codeName" : "AtlasError" }

The user I'm connecting with to the shell has the max permissions - it's atlasAdmin@admin role (I also tried withclusterMonitor@admin role)

I also can't seem to find any restart options in the mongo cloud manager web UI