Zero-sized transfers in PROCESSING will block all subsequent ones from a given user
Message in the log is something like
[Warn] Total size of all files in [D:\ProgramData\AUTOTRANSFER\PROCESSING\2018-07-18__13-58-03\USERNAME] is zero, NOT STARTING a transfer!From there on the given user can submit new transfers but the service will ignore them as long as this folder tree is still around, possibly even affecting all other users as well!