You have to actually connect via HTTPs, but because you left HTTP enabled on port 80, you likely haven't, so it isn't there.
2 solutions:
Specify HTTP or update the firmware (Due to demand, they added the option back in later firmware)
To specify https simply add it to the address in the addressbar via https://192.168.1.100 (clearly you would need to use your printer IP)
To update the firmware just grab it here