Samba share on second internal hard drive can't be accessed from Windows

I have Ubuntu server 20.04 on which I am trying to create samba share. There are 2 hard drives: one is nvme drive (/dev/nvme0n1p) and another one is normal HDD (/dev/sda)

The HDD is mounted by fstab with this line

/dev/sda /media/hdd1 ext4 defaults 0 0

The smb.conf (important parts) looks like this:

[global]
   unix charset = UTF-8
   workgroup = WORKGROUP

[erc]
   path = /media/hdd1/erc_bup
   read only = No
   valid users = erc
     #available = Yes
     #browseable = Yes
     #writable = Yes
     #create mask = 0777
     #directory mask = 0777
     #public = Yes

[erctest]
   path = /home/erc
   read only = No
   valid users = erc

And directory permissions are like this:

root@ercserver:# ls -la /home/
drwxr-xr-x  4 root       root       4096 Sep 10 18:28 .
drwxr-xr-x 20 root       root       4096 Sep 10 09:20 ..
drwxr-xr-x  5 erc        erc        4096 Sep 15 07:29 erc

root@ercserver:# ls -la /media/hdd1/
drwxr-xr-x 3 erc  erc   4096 Sep 14 14:37 .
drwxr-xr-x 3 root root  4096 Sep 14 13:27 ..
drwxr-xr-x 2 erc  erc   4096 Sep 15 11:04 erc-bup

So, [erctest] share is on nvme disk and [erc] is on HDD. When I go to Windows 10 PC and access server, it lists two shares (as it should be) [erctest] and [erc], but I can access with full rights erctest and cannot erc. The error says "Windows cannot access \\192.168.200.201\erc ,etc, etc. Error code: 0x80070043"

Please note the commented options in smb.conf [erc] section are what I unsuccessfully used in every combination.

So where is the problem? In my understanding settings for both shares are identical except that one is on primary OS disk and another on secondary HDD. Could the reason be ext4 format?

P.S. Additional detail- smbclient -L localhost shows:

        Sharename       Type      Comment
        ---------       ----      -------
        print$          Disk      Printer Drivers
        erc             Disk
        erctest         Disk
        IPC$            IPC       IPC Service (ercserver server (Samba, Ubuntu))
SMB1 disabled -- no workgroup available

What does it mean when is says SMB1 disabled -- no workgroup available. Is this related to my main problem?