Issue setting up my File Share witness

I am in the process of setting up a SQL Failover cluster over two availability zones in AWS.  My issue I am having is my File share witness is throwing me an error when trying to set this part up.  

set-clusterquorum -NodeAndFileShareMajority "\\EPMMNSDC1\Witness"

Gives me this error:

set-clusterquorum : There was an error configuring the file share witness '\\EPMMNSDC1\Witness'.
    Unable to save property changes for 'File Share Witness'.
    The parameter is incorrect
At line:1 char:1
+ set-clusterquorum -NodeAndFileShareMajority "\\EPMMNSDC1\Witness"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Set-ClusterQuorum], ClusterCmdletException
    + FullyQualifiedErrorId : InvalidParameter,Microsoft.FailoverClusters.PowerShell.SetClusterQuorumCommand

I have both my nodes as read/write on the share.  I am able to browse to the share from both nodes.

I try to run it through the GUI and i get this error: