Apple - What causes some Network Drives using SMB no longer connect to macOS Catalina?

The solution is in Catalina release note

NetBIOS is disabled in macOS 10.15 to speed up mounting, browsing, and connecting to SMB shares. Some older printers and file servers may require NetBIOS to connect. (51119111)

To enable NetBIOS, you can create or edit the /etc/nsmb.conf file. If your system doesn't already have an /etc/nsmb.conf file, use the following Terminal commands while logged in as an Administrator:

echo "[default]" | sudo tee -a /etc/nsmb.conf
echo "port445=both" | sudo tee -a /etc/nsmb.conf

To disable NetBIOS, you can safely delete the /etc/nsmb.conf file.

I managed to fix it after I enabled the "Allow guest users to connect to shared folders" for the "Guest User" under the "Users & Groups" panel.

First, I used the activation of NetBios, which seemed to arrange the trouble. But, in fact, that was not good.

So, I tried to unify Working groups of NAS (D-Link and Synology), iMac and MacBook Pro and then I put IP of my Box as WINS Server. And it seems to be the solution (for me).

D-Link NAS use AFP and Synology SMB protocol.

PS : Forgive my poor English....