Windows Drive mapping failed

[Juggernaut]

Hi

I have a TS-412 running RAiD5 and dedicated drive mapping within windows using the server name, about 3 weeks ago the mapping ceased to function with the message "network path not found, connection has not been restored". I can manually map using the IP address and also via the network drives option in Qfinder, however the name does not resolve in either windows machine. Have other QNAP nas boxes and compared setting and all appears correct and map in windows. their were no firmware changes to the NAS or updates to windows that I could pinpoint to the cause

Server is configured for Microsoft networking, DHCP, Workgroup
Running Windows 10 X64