I have just upgraded from Ubuntu 19.10 to 20.04 on my server that contains all my music and SONOS was unable to find my samaba share. After almost a whole morning of trying to figure it out I checked out the release notes for 20.04 (which I should have done in the first place) only to find that the new version of samba used explicitly disables SMBv1.
SONOS only supports SMBv1. After some more trawling of the net I found that adding the following line to the /etc/samba/smb.conf file, in the eglobal] section;
server min protocol = NT1
and restarting samba with the following command;
sudo systemctl restart smbd.service
my server started talking SMBv1 and SONOS could connect.
I hope this will save someone the time I wasted to fix the issue
Jim!