No Video Previews on shared hosting server

i am new in here.
I am sorry but I have this problem on my nextcloud installation (through installatron).
No video previews.
I have installed nextcloud on a shared hosting server.
I have asked my server provider to install ffmpeg as I have no root privileges (where the ffmpeg directory should be installed?)
Nothing has changed. All the videos uploaded before and after the ffmpeg installation have no previews.
I have also updated my config file as follow:
‘preview_libreoffice_path’ => ‘/usr/bin/libreoffice’,
‘enable_previews’ => true,
‘enabledPreviewProviders’ =>
array (
0 => ‘OC\Preview\TXT’,
1 => ‘OC\Preview\MarkDown’,
2 => ‘OC\Preview\OpenDocument’,
3 => ‘OC\Preview\PDF’,
4 => ‘OC\Preview\MSOffice2003’,
5 => ‘OC\Preview\MSOfficeDoc’,
6 => ‘OC\Preview\Image’,
7 => ‘OC\Preview\Photoshop’,
8 => ‘OC\Preview\TIFF’,
9 => ‘OC\Preview\SVG’,
10 => ‘OC\Preview\Font’,
11 => ‘OC\Preview\MP3’,
12 => ‘OC\Preview\Movie’,
13 => ‘OC\Preview\MKV’,
14 => ‘OC\Preview\MP4’,
15 => ‘OC\Preview\AVI’,
I have also added a cron job /public_html/occ preview:pre-generate -vvv but nothing happened.
I have installed the app Preview Generator and follow their instructions:
"The first time you install this app, before using a cron job, you properly want to generate all previews via: ./occ preview:generate-all -vvv

Important: To enable pre-generation of previews you must add php /var/www/nextcloud/occ preview:pre-generate to a system cron job that runs at times of your choosing."
But nothing happened. Or better the image previews are created but not the video ones.
Do you have any suggestions?
Is there a chance to have a support for this issue? Is this a problem that it will show up on every nextcloud installation?
Thanks in advance for your support.

Have you already checked the existing postings concerning this function?

You should also check if the ffmpeg program can be executed with the access rights of your web server user. By default the following pathes are checked:

$result = $exeSniffer->find($program, null, ['/usr/local/sbin', '/usr/local/bin', '/usr/sbin', '/usr/bin', '/sbin', '/bin', '/opt/bin']);