Network prob.

Hai Friends,

In my office net work We have 2 workgroups.
1.Officegroup
2.Mshome

Office group we are using for Account section.We are using Tally9 in accounts. Today morning onwards our tally server is not getting in network.if i click in any share folder in my network place one massage is showing ” You might not have permission to use this network”.

And when i click in view workgroup computer only my tally server is showing.

And am using symantec endpoint protection 11.0 in all syatem.

please help me to sortout this problem