The acceleration of a particle is found to be non zero while no force acts on the particle. This is possible if the measurement is made from

From an inertial frame of reference, if the particle is in rest then the net force acting on the particle will be zero.

So this scenario is possible with non inertial frame, when a particle is at rest w.r.t an inertial frame but when is observed from non-inertial frame of reference is seems to have an non zero acceleration although the net force acting on the particle is zero.