Unable to find template ...

When launching a libvirt host using a template, the "image" has to have the full path to the base template.

First go to Infrastructure > Compute resources > libvirt CR > Images and check that the image in use has the full path to the base image file on the hypervisor. Check with "ls -l PATH" that it's correct.

You may need to refresh libvirt's view of the images available using virsh pool-refresh default (or the appropriate pool name from virsh pool-list).