First of all, we apologize for the delay taken in our response. You must check what is blocking those IPs. The first thing that I would check is if their http requests arrive to apache (through the access log file
/opt/bitnami/apache2/logs). Otherwise, perhaps they are blocked at ~kernel level (through IPTtables). So as to check all the rule tables, you may want to check these commands:
iptables -vL -t filter
iptables -vL -t nat
iptables -vL -t mangle
iptables -vL -t raw
iptables -vL -t security
Let me know which of those two is, so as to guide you in the right direction.