Two things spring to mind
1. You have all new Sky Q Equipment
2. You have moved properties
1. Equipment is faulty. Get a replacement Q Hub
2. Do you have powerline enabled? If so, turn it off, it can cause dropouts and hence Sky disabled the feature on the Q router, but some users manually turn it back on.
3. Line fault as discussed.
Given the line crackling I am opting for possibility 3.