Universal Google Analytics Event Tracking Problems

I keep receiving a following error under Google GA Debugger plugin in Chrome:

Command ignored. Unknown target: undefined

In Google Analytics (GA) I do not see any events. I am using Universal Google Analytics and I attached it to a page thru Google Tag Manager (GTM).
When I change in GTM Tag Type from Universal Anaytics to Custom HTML Tag and paste manually GA code everything works.

Solution to the problem is to set a Tracker Name in GTM config

and raise events in a following way (Tracker Name is set to internalTrackerName):

ga('internalTrackerName.send', 'event', 'button', 'click', 'View Bookings');