Hey thanks for working on XCP-ng Center -- I find it a really useful tool.
Is this a README that describes how your project differs from XenCenter.
FWIW -- I had a similar problem with VMs going randomly down -- it wasn't windows but various BSD and Linux VM's. Sometimes they would run a few days, other times they would lock up every other day. Logs didn't help because when the VM locked, logs were not written. I even had the xcp-ng installation lock a few times, although it was usually on of the VMs. I started searching for faulty hardware and eventually SMART tested all the drives and mem86 the RAM. Turns out I had some bad RAM modules which I later RMA'd. With new RAM (after after thoroughly testing it), I haven't had any lock ups. I'm not sure this will help you at all.
@nikade Hey thanks for for the link. I ended up just using a LetsEncrypt cert rather than self signed. I think had to add a DNS host override on my router to associate the Local LAN address of the xo server with the domain name of the server contained in the certificate -- Like 10.0.1.50 ---> xo.example.com. Thanks for pointing me in the right direction on this one.