Hi
First, does the server changed IP in the restart ? can you do a "ping server" to validate it's still 10.0.0.20
Second point; It can happen with StrictNameChecking registry settings, please set it to 1 to disable it, to test it;
Registry location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters
DWORD name: DisableStrictNameChecking
DWORD value: 1