The visual aspect of our densified point cloud depends on several factors such as the image size, image content, and processing options. If you need to improve your results, you can indeed increase the Image Scale up to 1 and set a high Point Density.
This will produce 16 times more points than with the default options.
However changing these options cannot ensure you to significantly improve the results regarding the visual quality.
In addition this requires more computer resources (4 times more time and RAM).
Usually the spatial resolution of the densified point cloud cannot be higher than the GSD of the input images.
Point cloud settings when running step 2: https://support.pix4d.com/hc/en-us/articles/202557799#label1
Regarding your issue, what do you mean by errors? Could you send us some screenshots if you think this might be useful?
Did the processing of step 2 complete?