Netatalk Login problems on RaspberryPI with a disk HFS+

Question

I have just setup a RaspberryPI with the idea to use it as TimeMachine. I installed Netatalk and attached a usb disk which has been formatted with HFS+.

When I try to login from my Mac I get this error

This is my afp.conf

and if I check the list of disk it result to be mounted corrected

Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/root      ext4       15G  1.4G   13G  11% /
devtmpfs       devtmpfs  1.8G     0  1.8G   0% /dev
tmpfs          tmpfs     2.0G     0  2.0G   0% /dev/shm
tmpfs          tmpfs     2.0G  8.5M  1.9G   1% /run
tmpfs          tmpfs     5.0M  8.0K  5.0M   1% /run/lock
tmpfs          tmpfs     2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/mmcblk0p6 vfat      253M   53M  200M  21% /boot
/dev/sda       hfsplus   466G   69M  466G   1% /mnt/TimeMachine
tmpfs          tmpfs     391M     0  391M   0% /run/user/1001

and also the permission set on TimeMachine folders look fine

drwxrwxrwx 1 giulio giulio 4 Feb  1 09:22 TimeMachine

Any suggestion about which might be the issue?