could not be opened: failed to open stream: Operation not permitted code example
Example 1: storage/logs/laravel.log" could not be opened: failed to open stream: Permission denied
$ chmod -R 775 storage bootstrap/cache
Example 2: could not be opened in append mode failed to open stream permission denied
Reference link if giving a permission doesn't solved your issue
https://www.digitalocean.com/community/questions/the-stream-or-file-var-www-html-myscipt-storage-logs-laravel-log-could-not-be-opened-failed-to-open-stream-permission-denied