Your dog reaches the first step and stops. A treat at the top may look inviting to you, but the climb still feels too difficult or frightening to them. Forcing them up, pulling by the collar, or carrying a struggling dog can make the stairs a worse place next time.
If this is a new problem, or your dog is stiff, limping, or reluctant to jump elsewhere, arrange a veterinary check before training. Pain and mobility changes are easy to miss. Check the stairs too: slippery surfaces, open risers, poor lighting, or steep steps may be part of the problem. Keep access safely blocked when you cannot supervise, a fall is not a training step.
Let the first step be enough
On a safe, low, non-slip step, reward your dog for approaching, sniffing, or placing one paw on it. Let them retreat. Don't lure them so far up that they cannot comfortably come down, going down may be harder than going up. Use short sessions and stop while they are still willing to try. A dog who walks away is giving you useful feedback.
Once the first step is easy in both directions, invite one more. Support secure footing and keep the lead loose. If your dog freezes, pants, or scrambles, go back to a simpler setup. You do not have to finish a flight to call the session useful.
For an older dog or one with a medical issue, the answer may be a ramp, a different sleeping arrangement, or help from your veterinarian rather than stair practice. The goal is safe movement through the home, not proof that they can climb because you asked.
Sources: Humane Society of Huron Valley: Afraid of the stairs? (pain check and gradual practice). VCA Animal Hospitals: Creating a Comfortable Home for Your Mobility Compromised Dog.