The first thing I’d try is actually a reboot of the TV, by unplugging it from the wall for two minutes. Once you’ve plugged it back in, test, and also check for software updates for the TV.

@Redporti 

In addition to what @Airgetlam has offered you might check your settings in the sound menu of your Samsung to be sure they’re set to External Speaker.  I say this...as a software update may have downloaded automatically (with Auto-Update) and reset things to factory default. Just another guess 

Cheers!

I have done all that. It’s not recognising the beam. 

I have factory reset the tv & it automatically finds the sky box but doesn’t find the Sonos beam. The anynet+ is on but how can I check it’s working? Everything has been working well & then it suddenly stops working. 

Apart from checking the HDMI cable, I would remove all other HDMI connected devices, apart from the Beam. Then power off/on (not standby) both TV and Beam and see if it works then.

If it does work, my thoughts are that one of the other HDMI connected devices is stealing focus of the HDMI CEC controls. It’s a case then of finding the ‘problem device’ by cabling them one at a time back to the TV and when identified, turn off its HDMI-CEC controls, or use a HDMI CEC-Less cable or adapter. 

Ok I have been on to Samsung & they remotely went into my tv & reset the anynet+ port & now my beam works.