AAP failing on most VMs since v13 upgrade

[Amarokada]

We did the upgrade yesterday to v13.0.1 of Veeam.

On our jobs that backup from vSphere 8 via VIX with AAP most of the VMs are now failing with the error below. We also are using VCD as the entry point for Veeam.

"25/11/2025 05:37:03 Failed : Unable to release guest. Error: VSSControl: Failed to freeze guest over Hypervisor API, wait timeout"

Looking at the logs it seems to be going in a loop of uploading the vix agent and trying to connect to it (at least that's my take on it, it's quite a verbose log and doesn't make 100% sense to me).

Some VMs do work in the same jobs leading me think for the others they are simply timing out attempting to setup the vix agent and do the snapshot.

Before v13 these were backing up fine. We don't use the persistent agent in these jobs.

I'll raise a ticket but wanted to see if this comes up for others, or if it's a known issue.

Rob

[Gostev]

All known issues are documented in the sticky Top Issue topic in the main VBR forum and typically also have an associated support KB.
Please do not create forum topics about technical issues before opening a support case, as requested when you click New Topic.

[Amarokada]

Case #07898679 has been raised

Sorry I did this the wrong way around, but it's the day after some huge upgrades for us as a service provider so just trying to fire fight with all the avenues available. I see this isn't a current known issue from the 2 that are in the post you refer to, so currently it's just an "Issue".

On the plus side the actual upgrades to v13 have gone fairly smoothly, including for Nutanix which has changed things around quite a lot (no more vapp appliance).

[MatthewSt]

I am seeing the exact same issue. I'm using vSphere 8 and backing up via VIX with AAP.

I've logged a ticket for the issue and so far no luck other than to ask the team that looks after an affected server to investigate why VSS isn't working. I've backed up for years with V12 and this started happening the night we upgraded to V13. Some servers work, others don't, some combination of reboots/restarting VSS services and sheer luck seems to capture them occasionally without any rhyme or reason.

Extremely frustrating and so far, a frustrating response.

[RichT]

We have the a similar issue and for now it looks like Veeam sometimes tries to do Guestaccess from the Server where B&R is installed and not only the Assigned Guest Interaction Proxy, which failed because of Firewall ruels. And might have caused the timeouts to occur.
The job Chose the correct Guest interaction proxy at least in the Console Logs.

Im Currently opening a Case for this.

But for now you might want to allow the B&R server to be able to do all the Guest interaction things not "only" the designated Guest interaction proxy.
We could get the Job to be more consistent that way.