If you just upgraded PandoraFMS Community to the version 768RRR and the servers are down and in unknown state, this might be due that you are missing an important dependency necessary for the system in this newly released version.
Inside the logs of the server you will find the following error:
In order to get our server back up we just need to install the Thread::Semaphore package with the Perl instalation tool CPAN.
Simply execute the following command inside your PandoraFMS terminal shell:
cpan -i Thread::Semaphore
This way you will be installing the missing dependency needed for PandoraFMS to work properly and the service will be back up and active in no time.