I click on Tools->Connect Robot, Get Info, then on the Move button. I get the following error:
Where '<robot_name>' is the name of the robot I am attempting to move.
Also note that the controller log on that robot shows an entry like below:
Release: UIM 20.3
To move a robot from one hub to another within the same domain,
1. Select the robot in IM
2. Choose Tools->Connect Robot...
3. Click 'Get Info'
4. Click Move... button
5. Select the hub you want to move it to
6. Click Close
7. Press F5 to refresh IM
This should work for Windows as well as Linux machines, even when the machine is on a different subnet.
You can also try this -> In the Move dialog window, Select Use DNS Lookup option and specify the FQDN for the destination hub and click Ok.
If you encounter an error its mostly likely due to a communication issue. You can also login to the IM on the Primary hub or another hub and try it from there.
If you add Static addresses in the two hubs so that they can 'see' each other directly, this may help. For example, in the hub Name Services Tab window, for remote HubA, enter the IP for remote HubB. In HubB, enter the IP for HubA and try to move the robot once again. If none of the above suggestions work, you can manually change the robot.cfg to point the robot(s) to the new hubrobotname and hubip.
For moving a large number of robots please refer to the following KB Article:
How to move hundreds of robots to a new hub