This is one of the more tricky situation to distinguish between the object you want to detect and the surrounding noise like shadows and sunlight. There are topics about this in the section for guides & tutorials that explain in more detail, but basically you have to work with these red arrowed parameters.
Think about what you want to detect. If it is person the Blob detection algorithm might work better. With detection zones just allow the camera to see where in the field of view the object is moving. Try a low or very low Motion Sensibility if it is a person. However, a warning here sine the setting very low can filter out the movement. Threshold is the more tricky one. The level 0 is an automatic calibration more of the digital and electronic noise in the system. So the automatic Threshold can actually correspond to a higher value if set manually.
Is it possible to change the position of the camera?
Finally, what resolution of the video image is really necessary? A high resolution tends to be more sensitive or difficult to work with in this situation.
This was a compact version, but as mentioned it is a difficult situation so testing is necessary. There are of cause other more intelligent systems with correlation techniques, AI, pattern recognition etc, but then the price tag is a little bit different.