it seems that you do not have routing-instance with such a name:
 lab@test# run show route table ljl error: No routing tables matching specification.
lab@test# show routing-instances ? Possible completions: <[Enter]> Execute this command <instance_name> Routing instance name Test10 Routing instance name + apply-groups Groups from which to inherit configuration data + apply-groups-except Don't inherit configuration data from these groups test20 Routing instance name | Pipe through a command
lab@test# run show route table test20
test20.l2vpn.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both