Did you try coating again CoFeB just to be sure that the system is operable as s? Did you try changing the inductor coil in the matching network?

I changed the matching network today only , but the problem remains same

The deposition of a magnetic material onto the inner walls of your deposition chamber (and perhaps onto other components that yoy may have inside, for instance a collimator chimney on top of the target, etc) may alter slightly the magnetron effect in your sputtering source. FeCoB takes many magnetic field lines and as a result the magnetron effect decreases. You can try to change the configuration and/or strenght of your magnets below the other targets (MoO3, ZnO) and also increase the gas Pressure.