Box size not same in 2D classification

I import the relion 3.1 extract particle star file into cryosparc, and when I try to run the 2D classification and get error:

File “cryosparc_worker/cryosparc_compute/run.py”, line 84, in cryosparc_compute.run.main
File “cryosparc_worker/cryosparc_compute/jobs/class2D/run.py”, line 45, in cryosparc_compute.jobs.class2D.run.run_class_2D
File “/home/hendlab/software/cryosparc2/cryosparc2_worker/cryosparc_compute/particles.py”, line 37, in init
assert n.all(self.data[‘blob/shape’][:,0] == self.N_input), “All particles must have the same box size.”
AssertionError: All particles must have the same box size.

I didin’t know why there is different size of particles