rsync permission denied even root
I'm trying to sync two dir in a two different servers. At first, I'm running not privilege user since the directory has a read access to others. However, I encountered an error:
rsync: readlink "/data/docs/ARCHIVE" failed: Permission denied (13)
The permission of the directory ARCHIVE is:
drwxrwxrw- 2 foo users 4096 Nov 24 01:20 ARCHIVE
I decided to do rsync as root since it has no limitation in permission (am I right?). Now, when I run rsync using root, still I encountered Permission denied. I can't understand why it was denied when it fact it has read-write access. Other directory is fine.
Can anyone advise how to fix this problem? This is the first time I encountered this error using rsync