First the background:
LS210D series NAS, firmware version 1.65-0.12
NAS Navigator 2, version 2.90
Windows 10 Home edition
I can connect to the NAS no problem through Firefox, and the NAS did actually show up once in NAS Navigator 2. Unfortunately, it doesn't show up regularly through Navigator 2. The router definitely picks it up as the IP is found in the client list. Additionally, I am able to ping it with no problem.
I'm not sure what to do at this point. Even if Navigator 2 is unnecessary, it would be nice to get to the root of the problem.