SOLUTION IN SXOLEIO'S ORIGINAL POST
Thank you for using the Support Forum.I appreciate you coming to the forum to provide this answer. I am sure other people will have less frustration than you did because you posted this solution.
After so many days!!!! and after the official delegation in my country, Greece, refused to advise me over the phone, I finally found the solution. I searched here in the Xerox forum but I did not see the complete solution somewhere. So I write it, maybe someone else needs it.
After I changed the IP address : Port to 445 (old 139) – see at https://forum.support.xerox.com/t5/Copying-Faxing-Scanning/WorkCentre-6515-error-018-755/td-p/212993 - then i used Control Panel go to network and sharing center then go to change advanced sharing settings then to the section password-protected sharing finally I Disable password-protected sharing. I hope someone else finds this post helpful and did not suffer 4 days like me.
Solved! Go to Solution.