All the software agents appear in unknown, how to solve it?

There can be several reasons why all software agents are in unknown:

1. The Pandora FMS server is down, check that with /etc/init.d/pandora_server status that the server is running or in the server view, if it is not, restart the server to start processing the XML.
2.  Have a massive XML queuing in the /var/spool/pandora/data_in directory. You will have to move all the .data files to another directory so that the server processes the new ones that arrive. Once you are processing them well, you will be able to incorporate little by little the .data that have been moved previously in order not to lose data. We recommend during this process to have the token of the server configuration dataserver_lifo 1 for a faster processing, as well as to have the token dataserver_threads X with a number that corresponds to the amount of software agents as you have (remember that it can’t exceed 10 for a single server or 40 for all types of servers)
3. The tentacle service is down. The agents cannot send the XML files because the tentacle_server service is not active. Check with /etc/init.d/tentacle_server status that it is active, otherwise use the command /etc/init.d/tentacle_server start. If the service is running, go to an agent to see if it logs, it is possible that your agents have increased the monitoring and cannot send your file or that you have increased the number of agents and cannot process so many, for them go to the configuration file /etc/tentacle/tentacle_server.conf and modify the parameters of max_connections and max_sizes and increase the parameters.
4. The agents cannot contact the server. Check that there is not any impediment (iptable or external firewall) that is preventing that the agent files are received.