I am sorry eddie, but I am pretty sure that roots / snares etc do not cancel Teleport if it has already been activated. HOWEVER, Teleport cannot be used while rooted / snared etc because that prevents movement.
As others have said, if it is interrupted by someone other than yourself it goes on full cooldown.
Mowen i got that information at LoL wiki it says "by hard crowd control abilities such as stuns, roots, and silences." But then i searched up Crowd control on the wiki and these are the ones that popped up which are hard crowd control Airborne, Forced Action, Polymorph, Silence, Stun, Suppression. So i dont really know what the wiki is up to......
So: Suppress, Stun, Airborne (Knock-up, Knock-back, Fling, Pull/Drag), Forced Actions (Taunt, Fear, Flee, Charm, Polymorph, Silence.
I am sorry eddie, but I am pretty sure that roots / snares etc do not cancel Teleport if it has already been activated. HOWEVER, Teleport cannot be used while rooted / snared etc because that prevents movement.
As others have said, if it is interrupted by someone other than yourself it goes on full cooldown.