[Samba] FAILED with error NT_STATUS_WRONG_PASSWORD, authoritative=1

[basti]

Hello I have a Problem with one windows 10 client.

[2020/10/05 09:21:47.356628,  2]
../source3/auth/auth.c:334(auth_check_ntlm_password)
  check_ntlm_password:  Authentication for user [ap31] -> [ap31] FAILED
with error NT_STATUS_WRONG_PASSWORD, authoritative=1
[2020/10/05 09:21:47.356724,  2]
../auth/auth_log.c:610(log_authentication_event_human_readable)
  Auth: [SMB2,(null)] user [.]\[ap31] at [Mo, 05 Okt 2020
09:21:47.356700 CEST] with [NTLMv2] status [NT_STATUS_WRONG_PASSWORD]
workstation [AP31-PC] remote host [ipv4:192.168.0.54:49927] mapped to
[.]\[ap31]. local host [ipv4:192.168.0.100:445]
  {"timestamp": "2020-10-05T09:21:47.356848+0200", "type":
"Authentication", "Authentication": {"version": {"major": 1, "minor":
0}, "status": "NT_STATUS_WRONG_PASSWORD", "localAddress":
"ipv4:192.168.0.100:445", "remoteAddress": "ipv4:192.168.0.54:49927",
"serviceDescription": "SMB2", "authDescription": null, "clientDomain":
".", "clientAccount": "ap31", "workstation": "AP31-PC", "becameAccount":
null, "becameDomain": null, "becameSid": null, "mappedAccount": "ap31",
"mappedDomain": ".", "netlogonComputer": null, "netlogonTrustAccount":
null, "netlogonNegotiateFlags": "0x00000000",
"netlogonSecureChannelType": 0, "netlogonTrustAccountSid": null,
"passwordType": "NTLMv2", "duration": 4333}}

It looks that the client use NTLMv2.

The smb.conf on this server is:

root at server:/var/log/samba# egrep -v "(^#|^$|^;)" /etc/samba/smb.conf
[global]
   workgroup = WORKGROUP
   local master = yes
   preferred master = yes
   os level = 210
   server string = Samba Server
   log file = /var/log/samba/log.%m
   log level = 2
   max log size = 1000
   logging = file
   panic action = /usr/share/samba/panic-action %d
   server role = standalone server
   obey pam restrictions = yes
   passwd program = /usr/bin/passwd %u
   passwd chat = *Enter\snew\s*\spassword:* %n\n
*Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
   pam password change = yes
   map to guest = bad user
   admin users = ap19 ap30
   passdb backend = tdbsam
   security = user
   ntlm auth = yes
   usershare allow guests = yes
[homes]
...

When I use smbclient with username and passwd it works without problems.