Solved. The solution is related with “Local Group Policy Editor:Local Computer Policy:Computer Configuration>Windows Settings>Security Settings>Security Options>Network security: LAN Manager authentication level” or from regedit HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\LmCompatibilityLevel
From my many searches and tests during several days, i tested to change it from nothing (as it was my W10) to “Send LM & NTLM - use NTLMv2 session security if negotiated”, but it didn’t work.
But finally i saw the light with this post, [SOLVED] OS5 upgrade, no longer able to access PR2100 from Windows 10, CIFS: Authentication for user [user] has FAILED.
There are other options that work, as “Send NTLMv2 responses only” in my W7, or “Send NTLMv2 responses only. Refuse LM & NTLM” like in my other W10. I have selected finally this option.
