Why do I have to select "Performance(HTTP)"?

This is a validation problem. The error you are receiving is incorrect. I believe the error itself was corrected in 9.0.5.

 

 

Dr. Teeth is correct though. You can't actually use this rule with fasthttp (or without http).

 

 

You will need to add an http profile to your virtual and that is likely what is causing the misinformed error message. Please try configuring your virtual to include an http profile and then retry the rule. If it still does not work then you will need to contact support as we are not equipped to diagnose your system on this forum.