go into the settings on your windows pc and make sure you’re set on private and not public network. When its set on public, it won’t discover the network device. 

Is the vuescan connected to the wireless? 

The canon scanner is connected to the router via an ethernet cable so that it can be used by other devices (phones, etc.) on the network.  Vuescan is a software package on the Dell laptop.

The author of the software suggested  that UDP port 5353 might be blocking mDNS responses or Canon UDP port 8110 or 8612.  I don’t understand any of that.  How would I check of those ports are being blocked and if so, how to fix it?

Do you have your laptop set on private network? 

https://support.microsoft.com/en-us/windows/make-a-wi-fi-network-public-or-private-in-windows-0460117d-8d3e-a7ac-f003-7a0da607448d

Per your suggestion I set it on private network and restarted the computer.  Something else that might help.  The software does not see the scanner but it does see my pc camera which is connected via usb.  It shows up as a “source” in vuescan.  When I disconnect it, the software shows “file” as the source.  Not sure if that is useful information.  As I noted in the initial message, other scanner software see the scanner and work fine.  There is some settings on vuescan and the G36 that are causing the problem.

To open a port, I would suggest following the instructions which is on the below link:

http://arris.force.com/consumers/articles/General_FAQs/G34-G36-Port-Forwarding-Setup