There can be several reasons why people may be unable to verify you email. Most common are that these emails land in their spam inbox and get deleted. Other reason can be that they feel that you are trying to scam them, so they ignore it all together. Other reasons can be they find the email attractive enough to act, they might have been attracted to your website, but the email wordings may not be attractive enough. One of the worst mistakes you can make with your email marketing is to simply blast every subscriber on your list with the same message. Using list segmentation to send the right message to the right audience is critical to success with email marketing. Not to mention that when you are dealing with serious topics like health-related information, blasting the same content to all your users can have some bad results. List segmentation is simple to do.
You can read more here: https://www.forbes.com/sites/gabrielshaoolian/2017/05/10/6-ways-to-improve-your-email-marketing-campaigns-and-boost-sales-online/?sh=2088689362f0
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath