For your IC IBIS model, check that the [Diff Pin] is defined. Then for your SMA connector, create a dummy IBIS model with the same diff pin net names.
In HyperLynx, when you select the net, you may still need to define which is 'Output' and 'Output Inverted'.
The simulation should run now.
Alternatively, you can define net pairs under Setup > Differential Pairs