If you're experiencing this issue, ensure there are no special characters within the title of the document such as _: ! @ # $ % ^ & * ( ) - + = , . ; ? : / \ - as well as double spaces within the name.
If the issue persists raise a new case online and provide us with the file you are trying to upload, along with impersonation rights after confirming with the support engineer the email address you need to grant access to.