Query your DB mdl_files table for the name of that powerpoint.
'Encudadre General (6) ep (1).pptx' like so:

select contenthash,filename from mdl_files where filename like ''Encudadre General (6) ep (1).pptx';

If that query fails it might be due to the filename having () in it's name.

So change the query to all .pptx files

select contenthash,filename from mdl_files where filename like '%.pptx';

Could be a long list!

The contenthash information is both the real file name and it's location in the sea of files located in /moodledata/filedir/

Example of contenthash value:

few5bnwesbawerssery6

If you have command line access to server you can do a find for the that:

cd /path/to/moodledata/filedir/
find ./* -name few5bnwesbawerssery6
That will probably take a long time ... let it run.
If found, it will display a path like this:

/fe/5b/few5bnwesbawerssery6

See if that file is a pptx.   Again from moodledata/filedir/

file -b /fe/5b/few5bnwesbawerssery6

If the file doesn't exist, give moodle what it's looking for by cheating.

Again from moodledata/filedir/

touch /fe/5b/few5bnwesbawerssery6

will create a 0 byte file - no mime type, but moodle will find it and give you a chance to edit the link to it.

Good luck!

'SoS', Ken