Client Credential Prompts/IIS Error

Hi,

This morning colleagues reported EV credential prompts. I have followed the standard troubleshooting and see no issues so I began interogating the IIS logs.

I have the below snippet which seems relevant and would like to know what this means?

 2013-12-19 14:21:33 SERVER-IP GET /EnterpriseVault/ClientDiagnostics.aspx P=2&MSt=10&CSt=3&Ci=176115&Td=0&Fa=0&Host=CLIENT-FQDN&AId=1F97DABA2AD6AE04288C776C9E52F68471110000SERVER-DNSALIAS&OLVer=14.0.0.7012 80 DOMAIN\USER-IDCLIENT-IP EnterpriseVaultOutlookExt-V10.0.2.1218 404 0 0 46