It's not clear to me from your site what advantages your service has over already existing well-known services. Most people already have an email solution, so I think you need to make it clear how yours is different and why that might be better for them.

For example, I've already got Fastmail's standard plan ($5/month if purchased on a month-to-month basis). That allows 600 aliases, 8000 receives per day, 8000 sends per day, 30 GB email storage, 10 GB file storage. Your $5/month plan has bigger limits for some of those, and smaller limits for some of those, but I'm not seeing anything that tells me I might find your service useful either in addition to or as a replacement for Fastmail.

For email, I think a lot of people are going to lean toward an established provider in the hopes that this increases the chances of them being around long term.