Komentar resmi
It if is that far off it is likely that you did not include a ground reference image with your uploaded files. This would have made a more accurate elevation instead of using the GPS values.
The ground reference image does not need to be nadir but it does need to be taken to make this adjustment.
You can just take one instead of reflying the whole mission but all the images will need to be uploaded and processed again for it to be included.
You can see this post about adjusting the altitude manually:
https://support.dronesmadeeasy.com/hc/en-us/community/posts/203524813-Trouble-with-KMZ-files