We have had our puppy (German Shepherd, now 15 weeks old) now for about a month and a half. In that time, we have got him house trained (or so we thought). I know he is still in the teething phase, so we have been patient with the biting, but everything that we have tried to do to get him to stop biting isn't working. We have tried clicker/treats, ignoring bad behavior, yelping, bitter sprays, redirecting...nothing is working. He gets exercise and play time, but is getting aggressive with us regardless of what we do. Recently, he is now taking to pooping and peeing in the house again instead of signaling that he needs to go outside. We have a bell system that he rings when he needs to go outside, and he would ring it each time for a couple weeks and not have any accidents in the house. Now, he is ignoring it and going inside the house whenever and wherever he wants. We have him on a loose routine (my wife and I don't work typical 9-5 work hours, so our schedule changes from day to day) but we are at a loss for why the training isn't taking. Any advice?