Error 8921, 252 - can't update virus defs

PC not getting virus defs.  Gives 'error 8921, 252 unable to connect to network proxy server.'  We have 98 other PCs that are updating fine but a handful are not.  I uninstalled Symantec Cloud Endpoint Protection SBE, used the 2 wipe tools to remove it completely from PC, reinstalled Symantec Cloud Endpoint Protection SBE, and am still getting the same error.  Can anyone help?  None of the forums I looked at helped.