I have a DS212 and Im using it in home environment as an file server. Before start using it Ive updated DSM 40.2198. Im getting this error window very often :

My network settings are very simple. The workgroup name is the same on my PC and DS212 . Firewall is off. Using Avira Premium w/o firewall.
If anyone knows what can be the problem, please share.
Many thanks


