Logging does not work for me when using the simulator for a SmartApp I have written (never has). It does not seem to work for any error level. It neither shows in the box under the code editor window nor on the live logging screen. Does not work with using the simulator or the mobile app. I see events from the devices themselves, but not from my smartapp.
Has anyone else experienced this issue? If so, any advice on how to fix it. Without logging, debugging is near impossible. 
Do you have a UK Account or US Account?
If you are in the UK (with a V2 Hub), you must use the correct region URL – you probably are, perhaps, but this is a known cause for the problem you are seeing.
Your login and password will work for either URL; but they do not replicate the data from one to the other!
Thanks for the response! I’m in the US with a US account and a V1 hub.
Hmmm… I have lots of trouble getting the Simulator to work with “Virtual” devices in the IDE, but if I “Publish For Me” and then load the SmartApp and use real devices, then Live Logging is always fine.
The virtual devices seem to log OK (I’m using virtual presence sensors) as they are triggering an “arrived” event when I change the state of the presence sensors and I see this in the live log.
I am doing the “publish for me” that you suggest, and even then I’m not seeing the log lines in the SmartApp print out to the live log even though the code is clearly executing because my Switch is turning on and off.
Is logging working for everyone else?