if you get "unable to reach controller" in IM and "failed to retrieve information of Robot at controller" ensure communication robot-hub is working.
For UIM to work as expected we need the following Firewall rules enabled on all systems running a UIM robot.
1. Allow INBOUND TCP 48000 to 48099
Additionally on all robots that are also running hubs allow:
2. Allow OUTBOUND TCP 48000 to 48003
3. Allow OUTBOUND UDP 48000 to 48003
4. Allow INBOUND UDP 48000 to 48003
The controller, spooler or hub probes of a robot that is a hub, need both TCP/UDP and both inbound and outbound traffic allowed respectively on their ports (controller)48000, (spooler)48001, (hub)48002. Additionally every robot needs 48000-48099 TCP Inbound traffic.
Ports Documentation is covered here:
https://docops.ca.com/ca-unified-infrastructure-management/8-5/en/installing-ca-uim/pre-installation-planning/firewall-port-reference
Additional Article on ports:
https://support.ca.com/us/knowledge-base-articles.TEC1889526.html
Also check:
When I Double Click on a Probe I Get “unable to Reach Controller, Node:/Domain/Hub/Robot/Probe Error Message: Communication Error”
https://support.ca.com/us/knowledge-base-articles.TEC000002856.html
Other community post:
Controller probe (Unable to reach controller: communication error)
https://communities.ca.com/thread/241725061