ubuntu１４では、デフォルトSAMBAプロトコルがAWS共有ファイルサーバの版数にあっておりません。

/etc/samba/smb.conf を編集して、SMB3プロトコルをサポートしてください。

修正内容は、

#### Networking ####




# The specific set of interfaces / networks to bind to

# This can be either the interface name or an IP address/netmask;

# interface names are normally preferred

;   interfaces = 127.0.0.0/8 eth0




# Only bind to the named interfaces and/or networks; you must use the

# 'interfaces' option above to use this.

# It is recommended that you enable this feature if your Samba machine is

# not protected by a firewall or is a firewall itself.  However, this

# option cannot handle dynamic or non-broadcast interfaces correctly.

;   bind interfaces only = yes




client max protocol = SMB3　＜＜これを追記してください