I factory reset my iPhone 7 as I was selling out to a friend of mine, after the reset a pop up shows saying ACTIVATION LOCKED, So I login to my account from android and remove all the device but still the locked is still there?

iPhone 7 activation locked, when factory resetting, removed all the device as well as disable find my iPhone but the locked is still there, type in my apple ID and Password. A pop up sys iPhone credential cannot be used to unlock this iPhone. which is my apple ID and password, I can still use my ID and password from different or on web. please help! will be very much appreciated