Unable to establish authenticated client-server connection

[Jannik2606]

Hello!

Since a few weeks I keep getting Errors while trying to do the "Volume Only Backup".
I'm using the Veeam Backup & Replication Community Edition on Windows Server 2012R2.
They come at irregular intervals, sometimes it works sometimes it dosen't.
The error message is: "Unable to establish authenticated client-server connection."
I also got trouble with the "Manually Added" one.
Both of these don't appear in any relation to each other.
Details: "Backup agent installation is not requiredFailed to send certificate, but certificate is required for remote agent management."
Error: "No authority could be contacted for authentication"
Case ID: ("Case #04947648")

Kind regards

Jannik2606

[Egor Yakovlev]

Hi Jannik

Give it a shot to test this solution.

/Cheers!

[Jannik2606]

Hello Egor

You mentioned to change the Security Settings to "Allow All" but mine were already on "Not Defined" so this can't be the reason for the issues.
The other advice given was netstat -a.
As I did this and I found the right Local Address the "Foreign Address" next to it was ":0" with "State: LISTENING"
Should it be like this?
I've also tried at cmd: netstat -ano -p -tcp |find "11731"
It resulted in "LISTENING" and "4000" so I used "tasklist |find "4000"" to get further informations.
The result was VeeamDeploymentSvc.exe 4000 Services 0 31.140 K
Don't hesitate to contact me if you need further Information.

I appreciate every reply


Kind regards

Jannik

[Egor Yakovlev]

Well, since error pops every so often with no visible pattern, I would say some 3rd party intervenes communication. It is worth to check netstat again when you catch the error next time.
Let's see what support has to say about it.