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PHP Mailer Not Sending to Some Recepients

Last Modified: 2020-03-28

This is related to https://www.experts-exchange.com/questions/29173852/phpmailer-mailbox-unavailable.html

I’m testing sending out automated emails from http://selfregistration.iwscc.ca/email_test/index.php but not all are going through. For example, when I send to aleks@iwscc.ca I get “..mailbox unavailable or not local…”.

Please ignore “email sent” in this instance, because I quickly wrote the script without any error testing. However, it is sending to the following

aleks@aces-project.com (hosted by Microsoft, also mailbox is not local, but working)

apdcompany@gmail.ca (hosted by Google, not local and working)

One thing that I found strange when receiving the credentials for aleks@iwscc.ca as user is that said that if I want to encrypt emails, I need to purchase SSL. I know usually the SSL is for the server side, not client side. I am thinking that maybe that the iwscc.ca is some type of a budget server, but I cannot see how this relates to my script, which is at another server, and it should come down to sending a regular email. Manually, you are  able to email aleks@iwscc.ca.

What could it be?
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some mail servers will only allow whitelisted domains before the emails can reach them.
David Johnson, CDSimple Geek from the '70s
Distinguished Expert 2019

for encrypted mail s/mime you need a certificate attached to your email address.. then you and the recipient need to send a signed message to each other so you both have the others private key. You then can send encrypted s/mime mail 
Most Valuable Expert 2017
Distinguished Expert 2019

@APD Toronto,

If those are valid emails you might want to redact them or at least make your question private.

What you are experiencing is a common problem and has nothing to do with your code but rather the server you are sending from.

Best advice going forward - use a Mail service provider (like MailGun) - one that is professionally focused on server reputation and email delivery.
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