Cannot run 2D classification

I extract particles with Fourier cropping but showing error when trying to classify them. I used 624 box for extraction and reduced size to 256 to make the processing faster but end up with error.
Is the error is due to cropping or it cannot handle so many particles (1.9million)?

Here is the error:

: [CPU: 4.24 GB] Traceback (most recent call last):
File “cryosparc2_worker/cryosparc2_compute/”, line 85, in
File “cryosparc2_worker/cryosparc2_compute/jobs/class2D/”, line 88, in
File “cryosparc2_compute/”, line 274, in ang_to_radwn
return N * psize / ang
TypeError: unsupported operand type(s) for /: ‘float’ and ‘NoneType’


I believe this indicates that the “Maximum resolution (A)” parameter may have been overwritten to have the None value – could you confirm what this parameter’s value is, and if it is not set to a number, could you try setting it to its default of 6 (Angstroms) and re-running the job?