To help you, this forum would need details on what, specifically, you are doing and how, specifically, the Nest and your heating system are responding. You need to do some trouble-shooting to determine whether the problem lies in how the Nest is programmed, or how it's wired to the heating system, or in the Nest itself, or in your heating system itself. E.g., is this a new installation or was it working until recently? Does the heat come on sometimes but not when you think it should?
Here are Google's basic instructions for the E: https://support.google.com/googlenest/answer/9248184?hl=en#Learning-E (Sorry if this is too basic; maybe you are much farther along in the trouble-shooting process.)
