Problems with my mobile pages

I've got a problem. I noticed that some people can't click on the "read more" button while using the mobile site. A friend of mine told me the problem was in my aside (?). He marked something in a screenshot and i see i can't upload the screenshot here. So the only thing i can say about it is that he marked something with "position: sticky" and "top -203px". I don't know what it means because im not a technical person in this. So please help me out.