The ‘cURL error 56: OpenSSL SSL_read’ error is a server-side error. It can occur if the cURL library on your web hosting server is outdated or incompatible with your SMTP server.
Also, if your hosting server has a firewall feature blocking requests from your SMTP server, you’ll likely encounter this error.
Note that this error could also occur due to a temporal network issue. Keep in mind before troubleshooting the error.
Resolving the Error – Solution
Since this error is server-related, resolving it would be done at the server level and not from your SMTP plugin. Here are some steps to take when troubleshooting the error.
Temporal Network Issue
Earlier, we mentioned that it could be a temporal error. So, the first step we recommend is to wait and retry your SMTP plugin after some time. Often, doing this would resolve the error.
Firewall Blocking Issue
If retrying after a while doesn’t resolve the issue, then your firewall may be blocking requests from your SMTP server. You can temporarily disable your server’s firewall to see if it solves the issue. If it does, you’ll need to contact your web hosting and ask them to whitelist requests from your email service provider.
Outdated cURL Library
cURL errors are often caused by outdated libraries. If none of the methods above fixes the error, try updating the cURL library on your hosting server.
The exact steps for updating this library differ depending on your hosting provider. So, we suggest contacting your web host with the exact error details. They should be able to upgrade your cURL library and assist with troubleshooting the error.