For puppies it’s important that they are putting on weight as it is essential that they are getting enough nutrients during growing so they are healthier later in life. Additionally puppies almost always have a healthy appetite unless something is wrong. It’s because of this I strongly disagree with the comment “they will eat when they are hungry.”

I’d ask your vet what to do. I’d also change feeding arrangements as another suggested, by moving them further away so the puppy isn’t distracted. There also might be food allergies playing into this making the puppy not feel well from eating which is why they are taking coaxing... all of these are hypothetical and since it is a puppy I’d start with the vet. If this was an adult dog I’d try more things at home first but with this being a puppy this is essential growing time and setting their health for the future.