Download failed.: SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

Tried to verify that the CA cert is OK but didn’t seem to make any difference.

Then tried Fix SSL Update Error and it worked!. Have since deleted the ssl_verify.php file from server.

Step 1: Create the following folder if it doesn’t already exist:

/wp-content/mu-plugins/

Step 2: Create a new .php file inside of that folder, and name it ssl_verify.php or whatever you wish. Then inside of the file, include the following code:

<?php add_filter('https_ssl_verify', '__return_false');<span style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;" data-mce-type="bookmark" class="mce_SELRES_start"></span><br ?--> add_filter('https_local_ssl_verify', '__return_false'); ?>

Nothing else whatsoever should be in that file. No white space before/after the code, nothing. Nada.