Once again, the warning message is because you’re on an old version of All in One SEO Pack that is incompatible with PHP 7.3.
Again, once you’ve updated it to the latest version, the message will go away.
You should also disable debug mode on your live site: https://wordpress.org/support/article/debugging-in-wordpress/#wp_debug
Update to the latest version of All in One SEO Pack. You’re on 2.6 which is very outdated.
@machonne Please don’t contact me privately. That’s inappropriate.
Your OG image is set to wp-content/uploads/2017/06/img_ogp.png but 404s when I try to browse to it, so I’d say that’s your problem, not AIOSEOP.
You can find the documentation for keywords here: https://semperplugins.com/documentation/keyword-settings/
As Google doesn’t use them, this functionality is disabled by default.