Most likely a temporary error, as the message says it's "Too many connections" and that's at that moment. It's the MySQL/MariaDB server that's setup to handle only x connections at a time. If it's persisting you may be under "attack" of some scrapers like AI shit bots. It likely will go away eventually, but you could take a look at the web server logs and if it's a specific IP block that in .htaccess with a RewriteRule or SetEnvIf/Deny.

Some bots also obey robots.txt Deny entries but many don't. See also https://darkvisitors.com/agents but it's like fighting against windmills.