I built a custom finder that would select aggregates from a specific aggregate resource group in OM. When I test the finder directly, this works as expected. However when I add the finder to my workflow, this fails with Illegal expression.
Exact error is
Failed to evaluate resource selector. Illegal expression: VCI-Available-Aggrs
This message indicates that the variable that you are referencing is likely NULL. Is the variable name VCI-Available-Aggrs? Are you using the auto find option for aggregate inside of the command object? Might need to see some screenshots of the failure.
Since you are hard-coding the group name, you will need to put it in quotes. The current issue is that you are calling for a check of group named VCI-Available-Aggrs and since it is not in quotes, WFA thinks that it is a variable named VCI-Available-Aggrs. Change that and it should work like a champ. This is only required if you are hard declaring the value and not if you are using a user input to define.