If we assume that humans are conscious, then yes, it is possible for a machine to be conscious. The only arguments categorically differentiating humans from electronic machines are religious in nature. I define consciousness as having an internal model of the world that includes yourself, as well as your own though processes (at a lower degree of fidelity). This says how you compute things, not what you are computing…
There is one nonreligious factor that significantly differentiates humans from machines: that humans evolved, while machines were built by humans. There's an argument to be made that humans cannot understand consciousness well enough to build it, because consciousness is our only tool for doing that. Of course, this only applies to intentional creation of consciousness. It says nothing about the distinct possibility…
We can already generate big enough NNs that we can understand them in general (some areas get "specialised" in some way and more active in some conditions), and we know that the result is what we expect - but there's no way someone will take a look at the weights / resulting model and tell you what it does. I think we can create consciousness intentionally, but not understanding the process completely.