4.12.6 export HTML5 error

LogPlayLevel: Program.Main: AutomationTool exiting with ExitCode=1 (Error_Unknown)
LogPlayLevel: Domain_ProcessExit
LogPlayLevel: copying UAT log files…
LogPlayLevel: Completed Launch On Stage: Deploy Task, Time: 17.264040
LogPlayLevel: BUILD FAILED
PackagingResults:Error: error Launch failed! Unknown Error