I assume you used DriveHQ FileManager 4.5 to drag and drop the files.

The problem is very unusual as DriveHQ FileManager has been tested very carefully for many years. We need more info to trouble-shoot the problem. Does the problem happen only with one file (or very few files) or does it happen with any files? Can you upload any files now?

If you cannot upload any files, then the problem is almost certainly not related with DriveHQ software or service; the problem is likely to be caused by the router, or anti-virus / security software. 

If it happens only with few files, then the problem might be caused by random errors, which is usually caused by network instability. If a file failed to upload, in certain cases, the file info is still saved to the Database. DriveHQ has a "MagicUpload" technology, which can speed up uploading dramatically if the file has been uploaded before. However, if the file is corrupted, MagicUpload cannot correct the physical file. In this case, please delete the file and then upload it again. DriveHQ customer support can also help to delete the physical file on DriveHQ.