FreeBSD's mount_smbfs apparently supports only SMB1 and no newer version of the protocol.
By now (2019) SMB1 is horribly insecure and disabled by default on Windows, macOS, FreeNAS, etc.
As such, mount_smbfs is basically useless as it can't connect to any properly maintained server. I can only assume mount_smbfs has no maintainer. :(
Anyway, can the man page at least be updated to say that it only supports SMB1 ? Hopefully that will save people like me time determining why they can't connect to anything.
This has been recently documented in 13.0-CURRENT: https://svnweb.freebsd.org/base?view=revision&revision=339990
Maybe we could MFC that.