Command are running manually, but cron is not running
In order to close this post, I'll explain the solution.
There were 2 mistakes:
1/ the parametre cwd= (current working directory)  was incorrect.
2/ the way I use UIHostinger for cron was incorect.
My solution is:
0,30 * * * *   /usr/bin/php /home/u781989671/public_html/wp-content/plugins/civicrm/civicrm/bin/cv.phar api job.execute --user=myuser --cwd=/home/u781989671/public_html
best regards,
rv