When a student attempts to upload a file to their locker, the file does not seem to have been uploaded successfully. This link provides additional information about the Locker System.
The School Loop system
Before trying to upload the file to your locker, check to make sure the file name does not contain any illegal characters. The most common reason for failure is the usage of the ampersand (&) in the filename. This is a complete list of unsupported characters:
Ensure that none of these characters are included in the filename.
The file without unsupported characters in the filename should be successfully uploaded to the locker.