Error external backup to usb disk

[arsvendg]

I have had sucsessful backup to my usb disk for a long time, but at an unknown time in the last month I started getting this error:

"unknown error"

The description says the following:
[sender] could not find xattr #1 for Bilder/#Recycle
rsync error: protocol incompatibility (code 2) at /asustor/branch2_5_2016_02_02/x64_g1/source/rsync-3.0.9/xattrs.c(619) [sender=3.0.9]
rsync: writefd_unbuffered failed to write 4 bytes to socket [generator]: Broken pipe (32)
rsync error: received SIGUSR1 (code 19) at /asustor/branch2_5_2016_02_02/x64_g1/source/rsync-3.0.9/main.c(1431) [generator=3.0.9]

I tried to format the drive to ext4, as someone in another thread suggested, but it did not resolve the error.

Anyone have any suggestions?

[orion]

Mine is working fine. You'd better to send a support request to asustor to check it.