Denon AVR 6300 sound intermittently turns off then back on

As the heading explains. I have installed my new Denon AVR6300 but today there is something weird happening the sound intermittently cuts out then back on. on the screen of the Reciever when this happens the Dolby logo also goes away and the 5 speaker logo also goes away then back.

I have checked the source
Bluray
DSTV
Mede8ter
Nvidia Shield

all doing the same thing.

any ideas please guys.