Lost internet communication

Suddenly my HA seems to have lost internet communication. I cannot login to HA cloud and cannot update anything. LAN is fine - all sensors and local function is working well.
I can successfully ping all local network addresses but get ‘bad address’ error for any via internet.
I have checked my IP details and IPv4 matches my router and I have disabled IPv6.
I have connected via ethernet and Wifi and get the same for both.

This is the extent of my IT knowledge so I would welcome any suggestions of what further action I can try.