If people are not opening your emails, there might be several reasons for that:
What is a cold subscriber? Cold subscriber is a subscriber who hasn’t opened or clicked on your email for the past 90 days (it can vary).
We all hate spam emails in our inbox, so mailbox providers like Gmail and Outlook keep tracks of the reputation of each sender. If mailbox providers like Gmail thinks that you’re a spammer due to bad reputation, your emails will automatically go to the Spam inbox, and your subscribers will not get your emails. So, as a email sender, you should never spam.