“Active program deployed, board may require restarting”

Using the STM32L476RG MCU, whenever I try running any code the notification “Active program deployed, board may require restarting”. I have tried hitting the reset button on the NUCLEO board as well as unplugging the board but the same issue prevails. Any advice/ tips much appreciated.

The MBED version I am using is (1.4.3.1).