I ran into the same issue. Some SMB servers use NetBIOS and NetBIOS is disabled by default in MacOS 10.15 (Catalina).
https://medium.com/@gobinathm/how-to-access-smb-printer-shares-in-macos-catalina-10-15-17ea91d2c10b is a blog post that talks about it and lists the following steps to fix it.
By default, Apple has disabled NetBIOS in MacOS 10.5 to speed up SMB operations like mounting, browsing & connecting to an SMB share. If your own an SMB Printer/file server from the Past (i.e., Legacy or OLD) that requires NetBIOS to connect, then these devices won’t connect by default in Catalina like the prior version of MacOS.
In Order access these legacy SMB systems, you need to follow the below steps.
- Check if your system has/etc/nsmb.conf file. If one does not exist then doing the following.
touch /etc/nsmb.conf to create the file.
- Edit this file in your favorite editor & ensure the following lines are present in the file
Alternative, you can execute the below comments in your terminal.
echo “[default]” | sudo tee -a /etc/nsmb.conf
echo “port445=both” | sudo tee -a /etc/nsmb.conf
Simple delete the /etc/nsmb.conf