-a displays failed: Operation not permitted (1)#
Use -rltvz instead of -avz, so it won't prompt for insufficient permissions.
The error occurs when rsync wants to synchronize file permissions, but nfs generally does not allow users to change file permissions. Even mapping all users to admin does not allow changing permissions.
-a is a combination parameter, equivalent to all the combinations below.
-r or --recursive: recursively copy the contents of folders.
-l or --links: when the source file is a symbolic link, copy the link itself instead of the file it points to.
-p or --perms: preserve file permissions.
-t or --times: preserve the modification time of files.
-g or --group: preserve file group.
-o or --owner: preserve file owner (usually requires superuser privileges).
-D: preserve devices and special files (this is actually a combination of --devices and --specials).