Our Universe is currently 13.8 Billion Years Old.
After some 10106 years, our Universe will lose all its mass and energy and will become ‘inactive’ or ‘die’.
It will die as a ‘BIG FREEZE‘, because, due to no energy, it will become extremely (almost infinitely) cold!
This will happen because the universe is currently expanding and will expand forever. So, as it expands its density decrease due to increase in size. And as density decrease energy also decreases.
Space and Time will still exist after Big Freeze, but neither of them will have a meaning.