[Need Insight] From Redhat To NAS By FTP

[njcha]

Dear. Guys.

I made backup schedule from Linux server to NAS(TS-1263U) using the qnap app(backup manager) --> Remote Replications --> RTRR --> FTP.
while setup the schedule, I can figure out source folder and destination folder.
Looks like FTP Protocol works well.

When execute backup, backup manager show download status.
and, Without error backup manager finishing their job.
Looks like works well too.

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But, destination folder were empty.
while backup, I can see the one temp file (~$!#~000, size zero).
after backup, temp file were deleted.

I Looking for guru.
who can solve this issues?

thanks in advances.
NJ

Here is Linux server Information:
OS : RedHat
store more than giga byte, less then 2G
FTP set as passive mode.