I have never been able to get a decent focused in any night videos that i've taken so far in three years using my P4P. I have tried auto and manual, It is never close to acceptable and most of the time it is like very blurry. My night pictures are out of focus too !   What am i doing wrong ???  

Welcome coco60 ! Hope this Help

Thanks for all the links Bro. I'll have a look at these.

..Because my day shots are sharp.  If it would be a camera problem i guess day or night wouldn't be able to focus at all ?

Hello there coco60. I am sorry for the trouble this has caused and thank you for reaching out. With regards to the matter, yes there will be an issue with focusing if the light source is not enough meaning the sensor will having a hard time to select the subject and focus it. In addition to this I will post a DJI Forum Link that can help you with this matter. Thank you.

https://forum.dji.com/thread-70384-1-1.html

I am speculating here, but I wonder if it is the infrared light that is being noticed by the camera and out through as an image. I have the same problem with my security cameras. If so the image will be blurred as infrared focusses in a slightly different place than daylight. I am not an expert on DJI cameras but it might be worth a look.

Here is another thread that may be useful.  My take away was that even at the widest fstop (F:2.8)  that the minimum distance to subject, to set the lens to infinity is like 7 meters.  So why not just set it to infinity period?
https://forum.dji.com/forum.php?mod=viewthread&tid=207478

coco60 Posted at 6-10 14:22
..Because my day shots are sharp.  If it would be a camera problem i guess day or night wouldn't be able to focus at all ?

The most likely reason will be that the lens aperture is wide open and the slightest movement of the aircraft will blur the short. One of the main factors in taking night shots is have a perfectly stable position.