Fix Mac NAS Connection Issue

I'm experiencing a connection failure with my established Sinology NAS connected To a Mac mini.. The issue has only just been picked up; The volume hasn't been accessed for 4 or 5 months. Volume is used for photography storage through Lightroom... (Budget: $30 - $250 AUD, Jobs: Cloud Computing, Mac OS, Network Administration, Network Engineering, Network Security, System Administration, Technical Support, Troubleshooting, Windows Desktop, Windows Server)