failure audit in security log

[Guest Andy]

I am recieving a failure audit message in the security log with event id 537.

The reason for the error message is 'an error occurred during logon', and it

occurs when I run NTBackup. This is on a DC with a domain admin account.

Further down the 'Logon Failure' it mentions 'Authentication Package: NTLM'

and it notes the DC I am on as the workstation name.

 

One irregularity is that the FQDN is over 15 characters and therefore when

it mentions workstation name it is missing the last few letters. I have also

noticed that I can ping the two names and recieve a reply.

 

Anyone with any ideas how I get round this as the error message is

preventing me from backing up the system state.