Contact your network administrator to add the appropriate Files Folder URL to your to exceptions list on your firewall or proxy server:
  Also please ensure that your network administrator makes exceptions in the trusted sites of your supported browser (either FireFox or Internet Explorer) for the appropriate files folder URL as listed above.
  If the error persists after making these updates to your security systems and browser settings please document the following information and Contact Support and reference this article. 
  • Affected Blackbaud Hosting Services and Application username(s) and password(s).
  • The exact steps to duplicate the issue (click by click).
  • The name of the Blackbaud application affected.