Magento1 Email – How to Setup External SMTP Emailing on Local Magento

This is not a problem of Magento itself.

But if you send mails directly via a mail delivery agent from your webserver, the configuration of this one might be neglected.

I am assuming you send via the standard Linux mail delivery.

You have the following options:

1. configure your mail system on the Magento server to use a well configured mail server for example of your ISP
2. use an extension - AShroder's SMTP Pro module would fit.

One interesting provider which promises (untested) to take a lot of effort that your mail is actually delivered is Amazon SES - the module you mentioned also has a dedicated interface to Amazon SES.

The error you are getting from OpenSSL indicates that the SSL extension of PHP is compiled and loaded so no need to compile or load any .so or .dlls.

This is most likely a CA verfication issue - your SSL client (in this case PHP) is trying to verify the server's authenticity using root certificates; That's good - the only problem is this fails. Usually this means one of two things:

1. The server does not present a valid SSL certificate; This is unlikely for a well established email provider, I'm guessing you're using Google so this is probably not the issue.

2. More likely, your server does not have the up-to-date root certificates installed, or PHP does not know where they are. This is a configuration issue and solving it differs from server to server depending on your Linux distro and on how you installed PHP (e.g. from source, distro packages etc.). If you can provide more details about that, it may be possible to help.