Problem with txcode 5

When I have finished doinv pointing, and start to ranging then after some of txcode 9 appears, it change to txcode 5, and when I'm wait for a while then txcode 8 appears...but,the problem is after a few seconds txcode 5 appears again just 1 or 2 seconds...then it normal again to txcode 8, and in a few seconds it change again to txcode 5, then it normal again, it's happen continously... How to solve the problem to get txcode 5 dissapear?

I ask to noc and they said hub condition is OK, and I also have checked my cable, buc and feedhorn to...I need a suggestion