I am getting similar problem to that described here and other places:
Cannot connect to Azure File Share
but in my case it doesn't appear to be related to Port 445 being blocked. Test-NetConnection with port 445 works OK, and returns an IP address.
Credentials are stored using CmdKey, but I cannot access the share in Window explorer using the UNC path, and New-PSDrive returns an error:
New-PSDrive : The network resource type is not correct