I see there is a lot of warning messages in the PHP-FPM's log related to the max_children configuration. It seems the server is receiving more requests than the ones it's configured to received.
[01-Aug-2020 22:46:09] WARNING: [pool www] server reached max_children setting (5), consider raising it
Can you increase the max_children value to 25 in the
/opt/bitnami/php/etc/common-ondemand.conf file and restart all the services?
sudo /opt/bitnami/ctlscript.sh restart
Let us know if you continue getting the same errors when accessing your site.