127.0.0.1 is known as the loopback zone. It is typically used for developing & debugging network software, as well as facilitating inter process communication.
To allow access to the loopback zone you can make a rule like as follows:
Action: Allow
Protocol: IP
Direction: Out
Description: Allow Access to Loopback zone
Source Address: Any
Desination Address Type: Network zone
Zone: Loopback zone
IP Details: Any