What version of mix you're using? which smb settings within mix did you set(there are several)? What type of smb you're trying to connect to(smb version, authentication etc.).
You'll find a lot of information about smb within this and the FAQ tread from IronTechmonkey. Have you searched it already?
I did answer your questions.You simply did not answer any of my questions or give any information to help you further...
Even when everything was working fine before, nobody knows what YOU did or changed.
For me everything works fine, latest version, OP5, SMB
Q. What version of mix? I said latest.
Q. Which smb settings within mix did I set? I said everything default and I just added my computer.
Q. What type of smb. I said LAN SMB.