[COD] whispers disabled at random times

i dont know why, but for the past 3 months my whispers keep getting disabled and I have no idea why. It happens completely randomly and all it says is whats in the image. They are never disabled in the settings and it will just randomly work again. Then a few hours later stop.

any ideas as to why? i dont even use them really, other than to message one friend but its still annoying all the same.