not getting ip6 address i.e. bbbb::100 

im running 6lbr in raspberry pi with jessie os installed . when I start 6lbr with slip radio connected to rpi over usb port it shows "INFO: BR-RDC: Fetching MAC address" in /var/log/6lbr.log file. so i am unable to open webserver of 6lbr configuration. need help as soon as possible.
thanks in advance 