Fixing Veeam Backup & Replication Proxy Install Errors

Every once in a while I struggle a little to add a new Veeam Backup & Replication hot-add proxy. If you’re like me and seeing proxy install errors maybe some of these will fix you up. This is what worked for me on Windows Server 2016 when I was getting errorĀ 0x00000057, “Failed to create persistent connection to ADMIN$” and some other unhelpful messages.

If you’re using a hardened Windows installation all bets are off, since the goal of hardening is to intentionally disrupt remote access. I’d get it running with as close to a stock Windows installation as possible and then work from there if you need to secure things further. There are also ways to manually install the Veeam Transport Service that might be more helpful.

You might want to consider taking a snapshot before this work, so when you discover what fixes the problem you can revert the snapshot and just implement the fix cleanly.

  1. First, try specifying the username as the full “DOMAIN\Username” format when you add it to the Backup & Replication console. Don’t use the “.\username” format and don’t omit the domain part itself. If you are using local accounts you’ll want to specify “SERVERNAME\username” instead, using what the proxy knows as its name. This alone fixes 90% of the issues I’ve seen.
  2. If you aren’t using the Administrator account (and it’s a good idea not to) does the account you want to use have Administrator rights on the proxy VM, and the correct password? I sometimes forget to add the domain service account I created to the local administrators group.
  3. Check to see if you can reach the administrative shares on the proxy VM. Do this from the Backup & Replication main backup server itself by browsing to \\COMPUTERNAME\\Admin$ using the credentials you’re going to use for Veeam. This may mean you need to use “net use” to map it so you can specify a different username. If that works you should see the Windows directory on the remote computer.
  4. Didn’t work? Is the firewall enabled? For troubleshooting try adding an explicit “allow any” rule for all traffic to & from the backup server. If that makes browsing to Admin$ work then make sure you have rules to permit traffic between the proxy and the other proxies, and the proxy and the main backup server. Note that you can test this by just shutting the firewall off, but don’t do that unless you’re protected in some other way (hardware firewall, etc.).
  5. If the firewall is disabled and you still cannot browse can the backup server ping the proxy? Is there another firewall between them that’s denying traffic?
  6. If the firewall is disabled, they can ping each other, and you still cannot browse have you disabled remote UAC on the proxy VM? Open an administrator-level command prompt and run:
    reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\system /v LocalAccountTokenFilterPolicy /t REG_DWORD /d 1 /f

    Reboot the proxy VM and try again. At this point you probably can browse to Admin$, and you should take a moment to make sure your firewall is on and everything is secured again. If you still can’t get in I’d look at more fundamental issues, like time synchronization and DNS.

Good luck!