I have no writable permission to samba share

Question

I tried to create a file on a samba share with ver 4.10.6 but failed.

I used the folder /home/ppp/share for samba, with the following smb.conf:

#
#======================= Global Settings =====================================
[global]

   workgroup = MYGROUP

   server string = Samba Server

   vfs objects = full_audit
   full_audit:prefix = [%U:%g@%I]
   full_audit:success = all
   full_audit:failure = all
   full_audit:facility = local7
   full_audit:priority = info

   server role = standalone server

   log file = /usr/local/samba/var/log.%m

   max log size = 50

   dns proxy = no 

[printers]
   comment = All Printers
   path = /usr/spool/samba
   browseable = no
   guest ok = no
   writable = no
   printable = yes

[public]
   path = /home/ppp/share
   available = yes
   valid users = ppp
   read only = no
   browseable = yes
   public = yes
   create mask = 0777
   directory mask = 0777
   force user = ppp

I already did smbpasswd to add user ppp and the share name is public

But I only can read and write in existing files, but can't create file.

I tried two ways:

1. Mount it an another Ubuntu server which install samba ver 4.3.11:

   $ sudo mount -t cifs -o username=ppp,password=admin //192.168.80.108/public /home/otherppp/share
   $ touch /home/otherppp/share/hihi
   $ cannot touch /home/otherppp/test/hihi: Input/output error
   

2. Create new file from a Windows 10 share:

    Can't create file...
   

Can anyone help me?

=============== udpate ===============

When I update the samba version from 4.3.11 to 4.10.6, it solved.