I saw a link in a yellow box on my WP Admin panel informing me to Update Network. When I click is to update the network I get:
Your server may not be able to connect to sites running on it. Error message: SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
Note that I am not using the https protocol for my site.
So a search led to the following fixes, which I tested and verified as working.
Create a folder, which may be missing:
/wp-content/mu-plugins
Create a php doc inside that folder, I named mine upgrade_fix.php.
<?php
add_filter('https_ssl_verify', '__return_false');
add_filter('https_local_ssl_verify', '__return_false');
?>
Go ahead and run the network upgrade again, the issue should be resolved.
Thank you,