Why am I unable to access the shared drive from a different network?

Check to ensure the network you are on is authorized to access the shared drive.
Verify with the network administrator that you have the correct username and password for the shared drive.
Check the domain name of the network you are connected to is on the authorized list of networks for the shared drive.
Check if there are VPN settings that are uniquely required to authorize the network you are on to access the shared drive.
Check to ensure your hardware and software settings are compatible with the settings of the shared drive.