Extrinsic Calibration Issue

[BirBikram]

Hi, I am trying to SLAM with two USB camera. I followed the quick start guide. I am stuck at the extrinsic calibration part. When the window opens for pose calibrate, I press the spacebar as soon as the first camera shows the pattern and dot in the first camera. On the second camera, nothing happens! No matter how many times I repeat the steps. I get a massage in the terminal saying that "Warning: Grid size not equal pattern size! Grid size: [6 9] Pattern Size [6 8]". Not sure what am I doing wrong! Any help would welcome. Thanks Bikram