HC-05 can not use lower pins only 8 and higher
From the official SoftwareSerial Site: https://www.arduino.cc/en/Reference/softwareSerial (Section Limitations)


  Not all pins on the Leonardo and Micro support change interrupts, so
  only the following can be used for RX: 8, 9, 10, 11, 14 (MISO), 15
  (SCK), 16 (MOSI).