Symptoms

Unable to start the K2 Blackpearl server. When we do so we get the following error: "193761308","2016-08-22 09:58:24","Error","System","2001","ServerStartError","SourceCode.Hosting.Server.Runtime.HostServerEngine.StartHostServer","2001 Error Starting Host Server: There is an error in XML document (0, 0).","system","10.200.10.60","SRV:VInstall Dir]:Program Files (x86)K2 blackpearlHost ServerBin","193761308","41f6007c9552469f96fe03557ce1844f","" Error in starting the k2 service "Log File Not Found : ",",Install Dir]::Program Files....Host ServerBinDiscoveryService.config" Error "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.57 SMTP Client was not authenticated to send anonymous mail during MAIL FROM" This is on K2 4.6.8
 

Diagnoses

The root cause of this issue is due to missing DependancyService.config file in K2 Blackpearl/HostServer/Bin folder. Dropped the DiscoveryService.config file to the tInstall Dir]:Program Files (x86)K2 blackpearlHost ServerBin? folder and restart the k2 service. Corrected the parameter for "Mail Server" in the String Table on workspace, pointing to the correct SMTP/Exchange server. Management Console andgt k2 server] andgt Workflow Server andgt String Table.
 

Resolution 
 

Adding the missing config files to the  fInstall Dir]:Program Files (x86)K2 blackpearlHost ServerBin folder and restart the k2 service.