Crop has grey outline

i wanted to blur something out so I used the crop and blur method but when I croped it left a grey outline on the export pls help

Please explain exactly how you used this method

I duplicated the video and on the top track cropped out what I wanted to blur and then blurred out the whole track and I set the crop to transparent so you can see the track beneath

I recommend that you should try the “Blur:Pad” video filter.

Place Blur filter on top of Crop filter and the grey borders will disappear.
The order of filters is important and logical.
First apply the blur, then define the blurred area with Crop.

Thank you that fixed the issue

There is a filter set for this Filters > + > Sets > Obscure With Blur.