@olivierlambert Hi guys!
First of all, many thanks to @olivierlambert and @ha_tu_su for their quick responses and I apologize for my delay in responding.
I am very new to using XCPng, but it is such a good product that I am not going to rest until I learn it since I intend to replace the ESXi that I have with XCPng!
I was able to realize my problem, which is that as I am deleting and registering interfaces in the VMs to test, sometimes the VIFs are exchanged and the interfaces of the VMs are changed.
I solved it by deleting and adding the interfaces in the order that I want the VIFs to be assigned, and everything works perfectly for me, even the networks that are not interconnected to a physical port, but rather are to interconnect the VMs internally.
I already have everything I need working! Thank you very much for all the support, I see that it is a very active community and I hope soon to be helping too...
Martin Pedros