Cannot resolve local hostnames without internet

When I don’t have internet, the PCs in the office can’t resolve the network hostnames, and for example, we lose connectivity to the NAS. Therefore, we cannot access our files.
We don’t have a domain or DNS server, it’s just a network of a few individual computers with a home router acting as DHCP and providing the Internet. How should I configure Warp so that it can always resolve internal names (especially if I don’t have internet)?

I am using the Zero Trust Warp DoH service.

Regards

Add the domains to Local Domain Fallback: Local Domain Fallback · Cloudflare Zero Trust docs

Hi, thanks for the answer I just saw it.

We dont have a local domain, just 3 computers connected through a windows Workspace.