How to turn on SMB3 POSIX extensions in Samba server?

[Chris Han]

Hi, I want to use the SMB3 POSIX extensions in the latest Samba (with
SMB3.1.1, vers=3.1.1). By following the user manual, I have added the
"posix" mount option when mounting, but it shows the following error
messages.

Error messages:
[xxxxx] CIFS VFS: Server does not support mounting with posix SMB3.11
extensions.
[xxxxx] CIFS VFS: cifs_mount failed w/return code = -95

Mount option:
https://www.mankier.com/8/mount.cifs#posix%7Cunix%7Clinux
https://wiki.samba.org/index.php/SMB3-Linux

Mount commands:
mount –t cifs -o username=<user>,vers=3.1.1,posix //<address>/share
/mnt/share
mount –t cifs -o username=<user>,vers=3.1.1,posix,mfsymlinks
//<address>/share /mnt/share

Software and kernel version:
1. Ubuntu 19.04, Kernel 5.0, Samba 4.10
2. Ubuntu 18.04.3, Kernel 5.0, Samba 4.7

Example of using the "vers=3.1.1,posix" mount option: (Page 46)
https://www.snia.org/sites/default/files/SDC/2018/presentations/SMB/Steve_French_SMB311.pdf

How to turn on SMB3 POSIX extensions in Samba server?

Thanks.