Symptoms

Scheduled Hyper-V backup jobs may fail with errors similar to the following: avhypervvss Error <19328>: Unable to forward CTL sub-workorder to remote client [HYPERV-HOST03].avhypervvss Error <19366>: Unable to send sub-workorders to all remote clients.avhypervvss Error <41659>: Backup did not complete successfully.avhypervvss Error <43488>: PAX API 'beginfile:extents' reported error 32.avhypervvss Error <43490>: Failed in begin file C:\ClusterStorage\Volume23\WEBT01\WEBT01-OS.vhdx for incremental backup.avhypervvss Error <43486>: Failed to stream file '00000009\C:\ClusterStorage\Volume23\WEBT01\WEBT01-OS.vhdx...'.avhypervvss Error <43488>: PAX API 'endfile:extents' reported error 32.avhypervvss Error <43473>: Processing workorder in stream mode failed.avhypervvss Error <43475>: Plugin exited with code 536870920: cannot establish connection with server (possible network or DNS failure). Additional errors may appear in avtar and avagent.log: avtar Error <41439>: Using invalid token.avtar Error <10542>: DDR server open failed — Invalid API argument.avtar Error <10509>: Problem logging into DDR server.avagent.log:ctl_mcs_send ERROR <0001>: Failed to enqueue the MCS response for federated use case. Manual backups complete successfully.

Cause

The issue is typically caused by delays in the Management Console Service (MCS) on the Avamar Utility Node when handling DDR token requests.These delays result in token timeouts, especially during peak backup activity across Avamar and Data Domain grids.

Resolution

Reschedule the Hyper-V backup jobs to run during off-peak hours when Avamar and Data Domain systems are less busy. Example:If most backup jobs start at 8 PM, schedule Hyper-V backups to begin at 11 PM or later to avoid token timeout issues.

Support Cases