A container cannot be migrated via PVA. The following message is recorded to the migration task log:
,  : Can not connect to //var/tmp/10.25.34.21122.214.171.124:2010:2010:2.str Checking IP addresses on destination node
The issue is recognized as a product bug PCLIN-30084.
Install the tools updates on the server:
# vzup2date -m batch install --tools --self-update
No reboot is required after installing tools updates, however it's more recommended to install kernel updates as well and perform the server reboot:
# vzup2date -m batch install --core --tools --self-update --loader-autoconfig