Cycling the power may be a temp cure the problem. Specially if this system has a T1 or a PRI you need to run RAM check to clear the Errors from the Buffer in the processor. (PROG 00-51 LED 1 and 3 and Hold, PROG 00-61 LED 2 and 4 and Hold. You should run each of these programs at least twice.) WARNING !!! when you run these programs it will reboot the system !