I’ve bypassed the doorbell button, and the doorbell still did not work. What’s the most likely problem?

Check the transformer. You will have to find it. It might be in the attic, but it can be anywhere, you just need to trace the wire. If it makes a humming sound when the button is pushed, your problem is probably the chime. If it doesn’t make a sound, I would change the transformer to see if that’s the problem.