It is not a problem of wrong password. This happens after I have entered the correct credential. It shows a message line at the top: "Your input can't be opened: VLC is unable to open the MRL 'smb://....". It happens with multiple hosts and it happens on all Android devices I have.
Is this a bug? I turned on the log, but the log did not say the details about why it failed (just SMB2 failed messages).