Well. SMB is a filesharing protocol, so it makes sense your VMs still connect to the internet since their connection is forwarded by the host.
Off the cuff, I'd say to check your SMB settings for simple things: correct password and username, correct slashes, correct IP addresses/ranges, the usual, even pinging the other machines. Check security settings on the Windows side, too. Pitty you don't have just *nix machines. NFS mounts are way simpler.
On the mounts note, if you are trying to mount your Windows shares in fstab, try falling back to version 1 of CIFS (vers=1.1 option IIRC). My outer has a virtual NAS function and it took me a while before discovering that.
Other than that, w/o info, pretty pointless speculating. Troubleshoot order should start with Windows x Windows shares, then if they're fine, you know you'll have to check you Linux rigs, otherwise check the servers for config mistakes. About the best guesses I can make ATM.