[nova][train] live migration issue

Hello Guys, on train centos7 I am facing live migration issue only for some instances (not all). The error reported is: 2021-05-19 08:45:57.096 142537 ERROR nova.compute.manager [-] [instance: b18450e8-b3db-4886-a737-c161d99c6a46] Live migration failed.: libvirtError: Unable to read from monitor: Connection reset by peer The instance remains in pause on both source and destination host. Any help,please ? Ignazio