SSL Certificate Issue - Failed Pre-Flight Checks AWS PhP/MySQL

Hi there,

Thank you for taking a look.

I have a c-panel warning on an AWS hosted website (php/MySQL)...

"The system failed to acquire a signed certificate from the cPanel Store because of the following error: All HTTP and DNS DCV preflight checks failed!"

The website all appears to be working apart from my autoresponder/newsletter app, which I can't login to and when I go to reset password, I get:
"Severity: Warning
Message: stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages: error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number
Filename: libraries/class.smtp.php(1) : eval()'d code(3) : eval()'d code
Line Number: 344
Backtrace:
File: /home/executiv/public_html/arp/application/libraries/class.smtp.php(1) : eval()'d code(3) : eval()'d code
Line: 344"


I've had a look and believe that the solution could be below, but I am not technical/confident enough to make the changes:

https://forums.cpanel.net/threads/cpanel-25899-checkallsslcerts-fails-when-the-hostname-is-assigned-an-ipv6-address.648141/#post-2645433