linux – Cannot Connect to Samba Share from Windows 10

I have a Samba server version 4.1.11 running on Ubuntu 14.04. I cannot connect from Windows 10 (but I can from Windows 7).

The server and the clients are not on the same LAN.

The error message given by Windows is that the server is online but not responding. However the Samba logs say otherwise.

I have attached the logs for a failed connection attempt from Windows 10, and those for a successful attempt from Windows 7 (for comparison).

Briefly, unlike the successful attempt, the failed one starts with:

switch message SMBnegprot (pid 2855) conn 0x0

then it requests a number of different protocols before selecting SMB2_FF. Then, after some security negotiations, it switches to protocol SMB 2.???, then SMB3_00, followed by:

Server exit (NT_STATUS_END_OF_FILE).

The successful attempt selects protocol SMB2_10 from the start, but this protocol is not even requested by Windows 10.

Here are the logs :

Failed attempt (from Windows 10)
http://pastebin.com/M0xmBuY3

Successful attempt (from Windows 7)
http://pastebin.com/jF8VzaiA

I've added my smb.conf file in a comment (can't have more than 2 links with <10 reputation)