Most people struggle with this because they haven't refined their audience. No matter what your product is, there will be people who simply are not interested. So blasting promotional marketing to the world is going to expose your product to people who never would buy it, resulting in wasted time, effort, and money.

Instead, you need to build enough understanding of who your product appeals to that you can articulate who they are and understand the unique spaces that your specific audience pays attention to. Then you present your product within those spaces.

I actually had the same issue and then started posting in linkedin no matter what. If people like it they will react.