After following the screen replacement guide here: Fitbit Charge 2 Touch Screen Assembly Replacement, the display is...

There was no problem with the new display, the problem was in software. To fix this problem, I did a factory reset of the device. To do that, I followed the guide here: https://www.lifewire.com/how-to-factory-reset-fitbit-charge-2-4779440 (1) Go to the Fitbit website www.fitbit.com and log in. (2) Select the gear icon in the top-right of the screen and then select the device to be reset in the drop down menu. (3) Scroll to the bottom of the screen and select the option to remove the device from the account. (4) Add the device back to the account as was done for initial setup.