HI Rockstars, I hope everyone is doing well.
We are using Sonic Wall 3700 Firewall and Sonicwall Global VPN Client, and I noted after certain time (didn’t count exact time) I am unable to access network drives over VPN. It will show red cross sign on each network drive, and I have to re-connect the VPN to get the access.
Any specific configuration I can look at within Firewall? Appreciated your responses and time. 
I too have had this issue or the issue where GPO mapped drives simply just do not process. (The GPO issue I get, its’s not processing at login).
One thing I did discover isn’t about VPN but with power saver settings on laptops. Power saves will disable the radio and drop the connection. But that doesn’t sound like the issue you are having either.
Do you have an idle timer on your VPN connections setting?
On another note, I’ve moved away from GVC and transitioned to NetExtender…honestly, I like it better with the VPN Login option before you sign in…and the licensing is a little cheaper. To each their own.
Hi u/lovepatel898
and enable “Enable Dead Peer Detection for Idle VPN sessions”