We are using Mandrill for sending our emails. Our DNS are configured with correct DKIM and SPF records. This ensure a good deliverability.
If you do not receive any emails from stormz.me (email confirmation, invitations, ...) your email provider may block us. First, talk to your provider/IT departement to try to unlock the situation.
If you still have problems with our emails, you can also whitelist the IPs used by Mandrill. Bear in mind that this is not the panacea, as Mandrill regulary update their IPs. Look at their support article.