open a simple .docx word file..

[andreami1]

hello to everyone,
i installed a recente TS-453A.
i syncronized with my imac os 10.10.5 with QYSNC my "documents" folder.. all it's ok

BUT... if I try to open a simple .docx word document from a normal folder, stored in my NAS.. in my \nas\home folder.. is not possible and i receive this error window,
that i attached to this post

"impossible to open word document. it's possible that this "document is already in use, or that is not a valid word document etc"

i am a single user, in office.. with a single computer imac.

thanks in advance, for your support