quorum question

Hi,

We have setup a 2 node SQL 2016 AG, in our setup we did configure our Quorum as a file share on a server that is not part of the cluster.

When we manually run a failover the Nodes changing place, but it looks like that when one of the Nodes goes ofline ( shutdown the server or removing the netwerk cable) the failover dont take place.

Any idea why is this happening? or do I mis understood how the SQL AG works.

Thanks 

Shahin