I'm not familiar with that specific router, but the instruction manual (page 9) indicates it has a lock-on/lock-off safety feature:
Lock-On/Lock-Off Switch (Fig. 7)
The lock-on/lock-off
switch is located in the
handle on the right side.
The router is normally
locked-off.
To start the router, press
the thumb lock and
squeeze the trigger.
To lock the switch on,
squeeze the trigger,
press the thumb lock
forward and release the
trigger. To turn the router
off, release the switch. If the tool is locked-on, press the trigger
again and release the switch.
Make sure you press that thumb lock switch when squeezing the trigger.