After Plesk upgrade from 11.0.9 to 11.5 all websites shows Plesk default page.
Plesk is installed on Linux server in Amazon EC2 instance with local and external IP (elastic IP) like all amazon instance.
The website can be opened locally but from the outside of network it still shows Plesk default page.
By default, Amazon assigns each EC2-Classic instance two IP addresses at launch: a private IP address and a public IP address that is mapped to the private IP address through network address translation (NAT).
All requests are coming to the internal IP address when all domains are configured to external IP address.
If the Plesk is configured behind the NAT, all the domain's hosting must be having the internal IP address so that all the requests coming to external IP addresses will be forwarded to internal IP addresses of the domains. But the domains must be having the real IP addresses in their DNS records. So you need to make sure that, in Plesk > Subscription > Websites & Domains > DNS Settings will have the proper external IP addresses of the domain.
Make sure that the domain will have proper DNS records with the real (Public) IP addresses.
After every stop/start (if no Elastic IP is used) or after assigning a new Elastic IP to a configured Plesk instance, apply the command:
# /usr/local/psa/bin/amazon_setup_ip <new external IP>
Change the private IP address to internal and assign it to all subscriptions:
mysql -uadmin -p`cat /etc/psa/.psa.shadow ` psa -N -e" select name from domains;" | while read i; do /usr/local/psa/bin/subscription --update $i -ip 22.214.171.124; done