Samba & mpv: NT_STATUS_WRONG_CREDENTIAL_HANDLE

[peter_b]

Here's an error that MPV throws when trying to open a file from a network (Samba on Linux) share:

Using netbios name HOSTNAME1
Using workgroup DVA-PROFESSION.
gensec_spnego_client_negTokenTarg_step: SPNEGO(ntlmssp) login failed: NT_STATUS_WRONG_CREDENTIAL_HANDLE
[smb] Could not open from LAN: smb://guest@hostname1/...

This is actually just an info/warning which seems to appear when the login has an invalid username, but works fine if anonymous/guest access is allowed in smb.conf.

It merely seems to say: "You didn't provide me a valid username, the samba host says" - which then silently falls back to "map to guest".