Cannot send email to more then 20 people

Cannot send email to more then 20 people, I have setup my custom domain and want to send an invitiation far an event, when i sent the mail nothing arrives not even in spam, if i select one it gets sent. Even tried putting in BCC and sender email in to: and still i receive nothing... have checked all DNS records and they are fine, rather dull this why bother with paying if the one thing we want to use it for doesnt even work.. We have the standard license.