Thanks again for the suggestions. Audiphile 1 reminded me to double check my Cambridge MXN10 log in and (even though I would have sworn otherwise), I was still logged in. I signed out. AI still had the same problem. Then I signed out of the Tidal account on Auralic and signed back on. I have been streaming from a Tidal playlist for about an hour. So far, so good. I am now using my iPhone as the only smart device controller for both devices.
A couple of you recommended upgrading wifi/router interface. FYI, I am now using wifi connection but for first two years used ethernet connection with no problems. When the problem emerged a week ago I was using ethernet connection. Anyhow, if the G1.1 quits again I will look into these options.
Finally, Calieng's baseball bat solution has some appeal and I'm sure would provide some emotional satisfaction in the short term. However, I would then have to clean up the mess and perhaps deal with some personal injuries. Whatever its operational faults the G1.1 is pretty darned stout and I can imagine a glancing blow that did more damage to me than to it. Nevertheless, I'm keeping it on my list of "possibilities." For now, I'm following Steakster's advice to not give up the ship and sail on until all is well and truly lost.
As I was writing the damned thing up and quit. I: think I'll sign out and play Tidal on my desktop and see if any issues develop.