RHV veeam VM backup fails with "Error starting backup: Timed out during operation: cannot acquire state change lock"

Issue

• When trying to backup our RHV VM's using Veeam backup software, we get the following error: (vdsm.log)

2023-08-22 00:09:42,808+0800 ERROR (jsonrpc/5) [api] FINISH start_backup error=Backup Error: {'vm_id': '<VM-UUID>', 'backup': <vdsm.virt.backup.BackupConfig object at 0x7f70e21b3ba8>, 'reason': 'Error starting backup: Timed out during operation: cannot acquire state change lock (held by monitor=remoteDispatchDomainBackupBegin)'} (api:114)
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/vdsm/virt/virdomain.py", line 104, in f
    ret = attr(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/vdsm/common/libvirtconnection.py", line 114, in wrapper
    ret = f(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/vdsm/common/function.py", line 78, in wrapper
    return func(inst, *args, **kwargs)
  File "/usr/lib64/python3.6/site-packages/libvirt.py", line 797, in backupBegin
    raise libvirtError('virDomainBackupBegin() failed')
libvirt.libvirtError: Timed out during operation: cannot acquire state change lock (held by monitor=remoteDispatchDomainBackupBegin)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/vdsm/virt/backup.py", line 436, in _begin_backup
    dom.backupBegin(backup_xml, checkpoint_xml, flags=flags)
  File "/usr/lib/python3.6/site-packages/vdsm/virt/virdomain.py", line 162, in call
    return getattr(self._vm._dom, name)(*a, **kw)
  File "/usr/lib/python3.6/site-packages/vdsm/virt/virdomain.py", line 112, in f
    raise toe
vdsm.virt.virdomain.TimeoutError: Timed out during operation: cannot acquire state change lock (held by monitor=remoteDispatchDomainBackupBegin)