Puppies are often afraid of new things, and going outside can be a very overwhelming experience for them.
If a dog is exposed to too much at once, such as loud noises, bright lights, or unfamiliar people and animals, they can become overwhelmed and afraid.
Dogs need to be properly socialized to new experiences and environments when they are young in order to feel comfortable around them.
If a dog has had a bad experience outside, such as being attacked by another dog or being hit by a car, they may be afraid to go outside again.
Start by taking them outside for short periods of time and gradually increase the amount of time they spend outside.
Associate going outside with positive experiences, such as playing fetch or giving them treats.
Gradually expose your dog to the things they are afraid of in a controlled environment.