> for cifs share we not used AD,
This is going to be your problem. By default the EVS will have the smb-max-supported-version at 2 or 3. SMB2+ requires some kind of security signing to establish the session, and if you are not connected to an AD, the HNAS cannot process authentication.
The client attempts to connect, negotiates the highest SMB protocol version it can, provides signing credentials, and the connection fails because the HNAS doesn't know what to do with the credentials and can't sign the connection.
Best practice would be to connect the EVS to an active directory and use higher SMB protocol versions. If you cannot and want to ignore the security risks, you'll need to go in through the command line and turn off authentication and drop the max SMB version to 1
# vn hnasProd1
# cifs-auth off
# smb-max-supported-version 1
Again, that's extremely bad, means anyone/anything can connect to that share unchecked.