I have just upgraded Kubuntu 15.04 to 15.10 - all very nice. The machine is working well, and I can print to the Canon pixma mx420 with no problems as before, but both Skanlite and xsane return errors. xsane returns:

```
Failed to open device 'pixma:MX420_192.168.1.5': Invalid argument.

```

Also: 

```
scanimage -L
device `pixma:MX420_192.168.1.5' is a CANON Canon PIXMA MX420 multi-function peripheral

```

So the system is finding the scanner at the correct network address, but I don't know how to debug further. Note this all worked well before upgrade on this machine and the scanner has been tested from another laptop on the same network successfully - which is still on Kubuntu 15.04.

Thanks.