When libsmbclient is invoked by an application it searches for a directory called .smb in the $HOME directory that is specified in the users shell environment. It then searches for a file called smb.conf which, if present, will fully over-ride the system ${prefix}/etc/smb.conf file. If instead libsmbclient finds a file called ~/.smb/smb.conf.append, it will read the system /etc/samba/smb.conf and then append the contents of the ~/.smb/smb.conf.append to it.
libsmbclient will check the users shell environment for the USER parameter and will use its value when if the user parameter was not included in the URL.

The fix:
cd
mkdir .smb
cd .smb
touch smb.conf

Then, modify the ~/.smb/smb.conf file adding (NT1 is the protocol name for SMB 1.0, see « client max protocol » in :

[global] client min protocol = NT1

source: https://forums.debian.net/viewtopic.php?t=158196