In some cases, devices on your local network (e.g. printer, NAS) can be unavailable while connected to the VPN. This issue can be solved by simply changing the connection protocol to IPSec/IKEv2. Here is how you can do that:
Open the Atlas VPN app, click on Settings, and navigate to the Protocols tab. There, choose the IPSec/IKEv2 protocol.
And that is it! Now you should be able to access the devices on your local network.