There could be many reasons why your emails aren´t being received by the person that you are sending them to. Most of the reasons are beyond our control.
A common reason, is due to internet security software blocking the email. This means that software on the computer of the person you are sending the email to, or their ISP mailserver, has categorized your email as spam, and your email has been delivered to the users spam folder. Please ask the person that you sent the email to, to see if the email has been delivered to their spam folder.
Please also check that the email that you have sent, hasn´t been caught in your own internet security software.
Another reason, is the ISP of the person you are trying to send the email to, has blacklisted the IP range of the sending mailserver. This can happen if someone else using an IP number within the range, has been reported and blacklisted for spamming. This then can effect any other users that send emails within that blacklisted IP range. The only way to fix this is for you to contact the person or ISP blocking you, and ask them to add you to their whitelist.
Another reason is that your email to the recipient may have been delayed or queued. This occurs when there are high loads on the sending or receiving mailservers of the ISP. Also it can occur when there are spam or DOS attacks on the mailservers.
