Nighthawk Mr1100 - data connection disconnected - where is it switched on then!

Nighthawk MR1100 router stubbonly now shows that data connection is disconnected / no connection to the internet - on my dashboard, out of the blue after working fine for months and months when needed. All the help you get is it saying go to settings to switch it on. Roaming is on and phones, tablets and desktops all connect to it but no further and no where does it show something that should be on is off! It's like a test when frankly i have way more other things to be doing than this. Three different working SIMs (Voda, 3, EE - all checked and working) here in the UK and it shows the exactly the same problem - this item is ready for the bin. Basic question then where do you switch it back on to be connected.