In rare cases, the server build/start/stop operation may just take more time than usual (this part of the process depends on Amazon, not Bitnami).
Could you try to connect to your machine via SSH to confirm that it is available or not? If you are able to connect your machine, could you confirm that the services are running executing the next command?
sudo /opt/bitnami/ctlscript.sh status
After that, if the services are stopped. You can start them executing:
sudo /opt/bitnami/ctlscript.sh start