No preview for .mov files?

I’m trying to get the preview generator to create previews for my .mov files which are uploaded from my iphone.
When running ./occ preview:generate-all -vvv it seems from the output that the preview is created, but when I go to the folder in nextcloud, no preview is shown.
The preview is created for mp4 files, it’s just my .mov files from my Iphone that’s not working.

I’m using the latest nextcloud 14 with preview generator from the apps “store” in nextcloud.
My config.php includes:
‘enabledPreviewProviders’ =>
array (
0 => ‘OC\Preview\Image’,
1 => ‘OC\Preview\TXT’,
2 => ‘OC\Preview\PDF’,
3 => ‘OC\Preview\Movie’,
4 => ‘OC\Preview\TIFF’,
5 => ‘OC\Preview\SVG’,
),
ffmpeg is installed and the /usr/bin/ path is in my env

This is some of the output from running “./occ preview:generate-all -vvv”:
2018-10-09T21:24:36+00:00 Generating previews for /files/2013/20131224_164838.mov
2018-10-09T21:24:37+00:00 Generating previews for /files/NO_exif/20180715_173210.mp4

Any ideas why mp4 files are getting previews but not my mov files?