Vacuums, doorbells and traffic can scare a young puppy. The method here is gentle: start the sound so quiet it barely registers, hand out treats, stop after a minute or two, and raise the volume only on days your pup shrugs it off. Love My Puppy wrote it. Strong fear reactions are worth a vet or trainer. https://lovemypuppystore.bloggactivo.com/42506976/new-sounds-and-a-nervous-puppy-simple-fixes-for-tired-owners