[ubuntu] Simple Scan suddenly does not find Canon Lide 20 scaer

Since one month, I can use my old Canon Lide 20 scaer again, because I changed to Linux Ubuntu 16.0.4.

Now simple scan tells me, no scaer found.

I checked the cable, tested with an other cable
I checked the USB, pluged into the other USB of my Acer ES1-331-C0YK notebook
I checked the scaer, coected an other Canon Lide 20 scaer

I rebooted

Same problem.