KB1514: Veeam Backup Proxy server becomes unresponsive
https://www.veeam.com/kb151406.02.2012 · The Veeam Backup server or the Backup Proxy server becomes completely unresponsive when disks of a backed up virtual machine are being hot-added to the server. Cause If CTK parameters are enabled on the Veeam Backup server or on the Backup Proxy server, the Virtual Appliance mode cannot be used to back up machines with large disks. Solution
KB1577: Proxy Authentication Required - Veeam Software
https://www.veeam.com/kb157726.04.2012 · Go to Settings > Internet Options > Connections > LAN settings. Make sure that the Use proxy server for your LAN check box is cleared and save the settings. Restart the collector in the Veeam Extensions UI: open the Veeam Collectors tab, select the collector node on the left and click Restart Service. More information