X6 pixelates on restart

Comcast tech installed a new x1 system with one wired/two wireless x6 boxes. Worked flawlessly for several days. I had to unplug the router to move some cords and after it reset, both x6 boxes pixelated and were unwatchable. They are well within range of the router (one is two feet away). Internet speed is 150mbs. Came back 24 hours later and it looked ok. Thoughts on why the x6 boxes won’t work after a router reset?