I've followed all the instructions here for creating a custom widget.
I've put my widget in the C:\...\client\stemapp\widgets folder and also added the code below to the config.json file in my C:\...\client\stemapp folder.
When I try to test my widget using this URL http://<my machine>:3344/webapp/?config=config.json I only get a blank screen. Upon checking the errors in the Chrome developer console I see that I have an error saying Failed to load resource: the server responded with a status of 404 (Not Found) followed by this URL http://<my machine>:3344/http://<my machine>:3344/sharing/portals/self?f=json&dojo.preventCache=1426103768809
Also, I am unable to see my custom widget in the Choose Widget panel of the Web AppBuilder.
Can anyone help me with this problem please?
Thanks for your help. Unfortunately the question you refer to was another
one that I posted which I have now marked as not correct. We have some
issues here in our corporate LAN with portal access. Not sure what the
answer is yet.