I have been unable to use http://IotaWatt.local to connect to the IoTaWatt using Microsoft Edge and use the ip address instead but its seems to work using Chrome. Also I can ping the iotawatt using iotawatt.local.
Just in case anybody else had the same problem I updated the hosts file on my PC at C:/Windows/System32/drivers/etc/hosts and added (use you own iowatt IP address).
and now it works.
This might help somebody or somebody may know why or have a better solution.