SEE client fails to check in. Error Code : 407, proxy authentication required (seen in Techlogs)


Article ID: 156572


Updated On:


Endpoint Encryption


One possible scenario for this:

- IE  settings don't have a proxy specified AND/OR proxy override settings are in place for local servers

- SEE client is still  trying to hit the proxy server

- the '407 proxy authentication required' error message is seen as the proxy server is expecting authentication from any client hitting it.




This could be an issue with Internet Explorer's Automatic Web Proxy Detection (WPAD) feature. Its detailed in this Microsoft Technet article (, towards the very end:

Latest Wpad.dat Information Is Not Being Applied
The Wpad.dat file has been updated to point to a different ISA Server computer, but clients are still retrieving old settings.
Internet Explorer may cache the Wpad.dat file, and clients may retrieve old settings.
In Internet Explorer, clear the Automatically detect settings check box, and save the changes. Then restart Internet Explorer, select the Automatically detect settings check box, and restart Internet Explorer again. This forces a refresh of the Wpad.dat file. For more information, see the Microsoft Knowledge Base article 312864, "Automatic Proxy Discovery in Internet Explorer with DHCP requires specific permissions." As a workaround, delete the following HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections registry key entries:
DefaultConnectionSettings. This entry specifies the configuration of the default connection used by Internet Explorer.

SavedLegacySettings. This entry is a copy of DefaultconnectionSettings, and specifies the configuration used by network connections other than the default connection.

Do a search of the registry for the 2 registry values mentioned (DefaultConnectionSettings and SavedLegacySettings). The data type for these 2 registry values is not string, so any 'string values' within the data will not show up on registry searches. Open up the 2 registry values; Regedit's string conversion will show the string values within it. Clear the values completely if needed.