Error when trying to run dev/tasks/MigrateFileTask

Hi,

I’m migrating a SS 3.6 site to latest SS 4.9. Everyting succeed but can’t get the images/files migrated.
All the assets are uploaded to /public/assets/* folder. And try to run the dev/tasks/MigrateFileTask task.
But when I do I got an error:

# [Emergency] Uncaught UnexpectedValueException: The stream or file "/var/www/vhosts/*/../" could not be opened in append mode: failed to open stream: Is a directory

### GET /dev/tasks/MigrateFileTask?flush=all

Line  **110**  in  **/var/www/vhosts/*/vendor/monolog/monolog/src/Monolog/Handler/StreamHandler.php**

Do I something wrong?