Check the control line connection running from the CB unit to the bike's stereo unit. There's a 13p plug that ties the CB to the stereo, and odds are it's become intermittent.
Access is under the seat. The connectors in question will be obvious. Unplug and plug back in several times, then try to access the CB.
Also check the CB's power connection and fuse.
Thank you, I'll check them out tomorrow. Clearly something is disconnected somewhere for the bike's Audio System not to recognize that there is a CB installed.