Resilio Connect Agents use Tracker server as one of the means to discover each other. Each agent in a job connected to the tracker server configured in its Profile so as to communicate its own public and local IP addresses as well as discover other agents in the job.
By default, the Management Console has a tracker server installed on the same computer. So the default tracker address for other agents will be the same as the address of Management Console, listening port 3000. Additionally, some other tracker servers might be installed and configured.
The error appears only in cases when "Use tracker" option is set to "Yes" but the Agent was not able to connect to the tracker on the configured tracker address. In a profile that will look like this:
Here are the things to check and fix to regain connection to the tracker server:
1. check that the necessary tracker process is actually running on the configured address. That will be Resilio Connect Tracker service in Services for Windows; or that there's
tracker a process running from the same directory as Management Console process for Linux.
2. verify that the IP address of the tracker in profile is correct and there're basically no typos.
3. if tracker process is up and running and the address is correct, check the network tunnel itself, whether it is reachable from the network where the Agent is located. The simplest way is to use
telnet IP port command from the Agent's workstation.
If telnet connection fails with whatever error message, it mainly signals about connectivity problem between the hosts: the address is not reachable, or tracker port is not open and forwarded.
Look at the protocol reported in the Agent's error message - TCP or uTP. Make sure that all firewalls, NAT and other security software allow connection on given port by given protocols.
4. check if the Agent's profile has specific protocols to try configured via custom parameter
tracker_protocols. If you don't see such parameter in the Agent's Profile, it means that default protocols are used - both TCP and uTP. If there's only one protocol configured, you might want try try the other protocol - edit the Profile and add the missing protocol.