Hi @mariaBui
I guess you are uploading audiovisual footage (for images is similar case).
Please, first check what files are stored in your system.
To do this, go to section Audiovisual, and select the record where you are upload the file.

Then, select (click) the Audiovisual component in your Dédalo system, and select the first tool from the top toolbar (Media versions).


Here, you can see the full list of audiovisual files for this component in different qualities and formats.
If the list is empty, probably you have a permissions problem in server side with PHP and the upload directory.
Please, review on the upload tool that the System temp dir is accesible and writable for PHP and your file is accetable in terms of extension and size.

Besides, check that configuration (config.php) constant DEDALO_UPLOAD_TMP_DIR value exists and the directory is writable for PHP.
I hope you find this information useful.
Best