error catalog file ......wsusscn2.cab verification failure

tried 3 times"../static/StaticDownloadFiles-modified.txt" [1]
Last-modified header missing -- time-stamps turned off.
2016-07-26 21:49:19 URL:http://download.wsusoffline.net/StaticUpdateFiles-modified.txt [144/144] -> "../client/static/StaticUpdateFiles-modified.txt" [1]
Tue 26/07/2016 21:49:19.67 - Info: Updated static download and update definitions
Tue 26/07/2016 21:49:20.00 - Info: Downloaded/validated mkisofs tool
Tue 26/07/2016 21:49:20.15 - Warning: Integrity database ..\client\md\hashes-wsus.txt not found
Tue 26/07/2016 21:49:20.84 - Info: Downloaded/validated most recent Windows Update Agent installation and catalog files
Tue 26/07/2016 21:49:20.84 - Warning: Deleted unsigned file "C:\Users\Bill\Documents\Updates\wsusoffline\client\wsus\WindowsUpdateAgent30-x64.exe"
Tue 26/07/2016 21:49:20.84 - Warning: Deleted unsigned file "C:\Users\Bill\Documents\Updates\wsusoffline\client\wsus\WindowsUpdateAgent30-x86.exe"
Tue 26/07/2016 21:49:20.84 - Warning: Deleted unsigned file "C:\Users\Bill\Documents\Updates\wsusoffline\client\wsus\wsusscn2.cab"
Tue 26/07/2016 21:49:21.11 - Error: Catalog file ..\client\wsus\wsusscn2.cab signature verification failure
