Hotspot not working + udev rule?


I normally connect my OSMC via wifi, and it has never given any problem, but I have not been able to make the hotspot work.
I have a RPi2 and I am using the OSMC program that comes with Kodi (by the way, the network menus are very very slow.
I have my RPi disconnected from eth and wifi. I enable Hotspot functionality and get “Error enabling hotspot - see log for details” error. What log do I want to look at?.

Apart from using my device at home wher I have wifi, I would also like to use it on my trips. I will find myself in situations where I have TV available but not wifi. Starting a hotspot, and connecting my phone to it to use it as a remote control seems like a perfect solution to watch movies/listen to music.
My final goal is to create a udev rule that would run the script that starts the hotspot for me, as I do not carry a keyboard with me in my trips. The udev rule may be triggered by connecting some specific USB drive, for instance.

I know how to create the udev rule, I created one to shut down the Pi in a controlled way when I run into problems by removing the wifi usb connector.

Any advice will be very welcome.