Ubuntu – Unable to creatre Samba shares in 20.04

I share three or four folders over my network, but since upgrading to 20.04, I am unable to create new ones. When I try, I get the error message

'net usershare' returned error 255: net usershare add: cannot convert name "Everyone" to a SID. > An invalid combination of parameters was specified..

Existing shares continue to be accessible.

I tried the fix given here but the line in question is already in my /etc/samba/smb.conf file.

Edit: Entering net usershare info –long yields the folowing:

[C&L Docs]

path=/home/laurie/Sync/C&L Docs

comment=

usershare_acl=S-1-1-0:F,

guest_ok=y

Entering testparm yields:

Load smb config files from /etc/samba/smb.conf
Loaded services file OK.
Server role: ROLE_STANDALONE

Press enter to see a dump of your service definitions

Global parameters

[global]

client max protocol = NT1

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

logging = file

map to guest = Bad User

max log size = 1000

name resolve order = bcast host lmhosts wins

obey pam restrictions = Yes

pam password change = Yes

panic action = /usr/share/samba/panic-action %d

passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .

passwd program = /usr/bin/passwd %u

server role = standalone server

server string = %h server (Samba, Ubuntu)

unix password sync = Yes

usershare allow guests = Yes

idmap config * : backend = tdb