The computer’s performance and program configurations may be the vital factor affecting the capturing, so you can try to fix your issue:
Please move to "Preferences" > "Output" to reset the related items. Make some configurations as following:
- choose MP4 format in the drop-down;
- select H264 in Video codec;
- change the frame rate to 20 fps;
- select Middle or High quality.
Now, please record the screen activity again.