This is probably due to there are more connections now that the ones you had before. I saw this error in the PHP-FPM's log
[16-Sep-2020 17:56:09] WARNING: [pool www] server reached pm.max_children setting (300), consider raising it
300 is a really big number so you should be receiving more requests now or a bot/attacker is requesting your site now. Can you take a look at the Apache's access log file (/opt/bitnami/apache/logs) to see if there are malicious requests to your site?
50X error message means that there is an internal problem. As I showed above, the server is reaching the limit and that's why you get that error message.
Could you please clarify this? Do you mean that when you kill those processes, the app works properly?
You need to use the
sudo service bitnami command to restart the services