Standing before the gates of hell is read as a threshold into your own darkest material — fear, shame or anger you have avoided. Tradition sees it as the start of a descent that can also lead to understanding.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.