isc-dhcp-server6 main process ended, respawning

[shafi at bbnl.co.in]

Hi,


     I have installed ISC-DHCP-SERVER in ubuntu server 12.04 64 bit 
operating system.It was provide both ipv4 and ipv6 for customer.Now it's 
suddenly stopped to provide ipv6 address it's provide only ipv4  not 
ipv6. in log file it's showing some error message.Please help me to 
solve this issue.

ERROR :

   init: isc-dhcp-server6 main process (4192) killed by ABRT signal
[ 7274.104951] init: isc-dhcp-server6 main process ended, respawning

Regards
shafi