Unable to access network shares

i have a HP N40L microserver. its been flawless since i bought it.

it runs WHS 11 and its not setup complicated (runs plex, sabnzb & crashplan)

drives are pooled with drivebender which has some redundancy wizardry built in.

for years (6 or 7) its been running exactly how i need and has survived multiple house moves and multiple ISP switches.

the other while i was copying files to it i got an error and i was no longer able to access any shared folder.

i logged in via RDP and checked the health of the drive and they were all fine. i can ping the server from my PC & can still access sabnzb web access and plex can still see and play the files on the server.

the only change of late has been an ISP change.

anyone have any ideas? ive googled and googled but no avail.