check the logs /var/log/vdsm/import//xxxxx by loging into specific host where the vm import getting, if there is a vcenter time out happened, follow this https://bugzilla.redhat.com/show_bug.cgi?id=1848862 It looks like virt-v2v creates too many HTTP sessions to the VCenter and it results in 503 error in VMware's VCenter services. * Workaround for the HTTP method * I found a workaround to allow VCenter to accept as many sessions as possible you can change the file /etc/vmware-vpx/vpxd.cfg on the VCenter's server and add inside the <vmacore> XML tag the following XML: " <soap> <maxSessionCount>0</maxSessionCount> </soap> " You shouldn't replace all the <vmacore> contents, just add the above lines inside. It will look something like that: " <vmacore> <cacheProperties>true</cacheProperties> <soap> <maxSessionCount>0</maxSessionCount> </soap> <ssl/> <threadPool> <TaskMax>90</TaskMax> <threadNamePrefix>vpxd</threadNamePrefix> </threadPool> </vmacore> "