Anyone use premier elements 10? Noob issue!

[Ultra_Extreme]

Hi guys, just started outputting my drone footage in premier elements 10, when i render out the video at 1080p i get a weird letterbox effect in the end video.

The source is 4k, dont even know where to start looking tbh!? any of you experts know what im doing wrong?

Example

https://youtu.be/ZJLWzW4IO4A