After a restart of my VM instances my site is down. I checked the IP address, but it didn't change. Do you have any ideas about what is wrong and how to fix it?
I run WordPress (Bitnami) on a Debian-based OS. I use Cloudflare CDN. I understand that on stopping a VM it doesn't keep the settings. Can I restore them?
About your last error message
Syntax OK (98)Address already in use: AH00072: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down AH00015: Unable to open logs /opt/bitnami/apache2/scripts/ctl.sh : httpd could not be started Monitored apache
I have found similar errors due to Nginx, it could happen if you have it installed and it is creating conflicts. make sure you remove it as follow:
sudo apt-get remove nginx nginx-common
sudo apt-get autoremove #to remove unneeded dependencies