Truth is being, untruth is non-being , and between the two there is a world of dreaming-- it carries the qualities of both. And Mind is the source of dreaming, so the Mind is illusory. The Mind is the source of all Maya.
Everything comes from nothing an deverything moves into nothing : that is the meaning of Maya. It does not mean unreal , because even the writing on the sand is real. Even the writing on water has its own reality , altough it is very fleeting.
The Mind knows only the dream, the illusion. A life lived through the mind is a life of dreams. That is Maya. The Mind is the origin of the Maya.