I have this problem where people (whom I've never contacted before) don't get my emails??!! It happened with so many that I'm sure it's an issue with my own email address (and not the device I'm using) and truthfully, it put me in many uncomfortable situations. But after getting an email from them first, they could receive my replies so the issue is with new addresses because I don't have a problem sending emails to old addresses. I hope you can look into it and fix it soon.