Without pictures its hard to say for sure but after 2 hrs if the chicken was underdone , the temp was set too low.
Please keep in mind that a lot of things cooked this way will seem underdone compared to traditional methods .
I generally like to follow Kenji’s recipes here , and his temp for "tender and juicy " is 150 deg, and “traditional firm and juicy” at 160.
Believe it or not a few degrees difference make a huge big deal.