Deeplabcut 3D cameras calibration problem

Hi. After I finish delete any bad pairs from the coner and calibration_images files, when I did deeplabcut.calibrate_cameras, it have following error(I have 27 pairs images).How to solve this problem?:

deeplabcut.calibrate_cameras(‘Z:\Anaysis Codes for Data (MATLAB, DLC, etc)\DeepLabCut\Ran\Cam01-b-2021-01-20-3d\config.yaml’, cbrow=6, cbcol=8, calibrate=False, alpha=0.4)
error: OpenCV(4.4.0) C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-wbmte9m7\opencv\modules\calib3d\src\calibration.cpp:3336: error: (-2:Unspecified error) in function ‘void __cdecl cv::collectCalibrationData(const class cv::_InputArray &,const class cv::_InputArray &,const class cv::_InputArray &,int,class cv::Mat &,class cv::Mat &,class cv::Mat *,class cv::Mat &)’

(expected: ‘nimages == (int)’), where
‘nimages’ is 54
must be equal to
‘(int)’ is 27

Here are the example calibration images