Windows 7 computer cannot access shared folders on El Capitan (even when Samba is turned on and on the same workgroup)

Greetings,

I have a Windows 7 computer (Enterprise edition) on my workplace network. I am trying to access a Mac OS X share on the same network. Both computers are on the same workgroup and samba sharing is activated on the mac. When I enter the Mac name (or its IP address) when I'm trying to mount a network drive in Win 7, the login credentials window do appear on my Win7 computer. However, credentials are NEVER accepted. I tried entering credentials by themselves or in the format of "nameoftheMac\login".

I also created a user account on my mac dedicated to sharing and followed the same procedure as above. Nothing worked.

Any ideas ?

Thank you,