At 4 months old your dog walked into the crate and went to sleep. At 10 months old they plant their feet at the doorway, or go in and whine, or get out the moment you turn around.
Why a crate stops working in adolescence
Usually one of three things has changed. Your dog has outgrown the space and cannot lie flat. The crate has become the thing that predicts you leaving. Or something unpleasant happened near it and nobody saw.
There is a fourth, and it is worth ruling out early. A dog who is uncomfortable lying down on a hard surface may be telling you about their body, not the crate.
Check these before you train anything
Measure it. Your dog should be able to stand without ducking, turn around, and lie fully stretched out on one side. Most adolescent crates are one size too small.
Add real bedding, thick enough that a hip is not resting on plastic or wire. Then move the crate to where the family actually sits.
Book a veterinary examination if your dog is also slow on stairs, reluctant to jump into the car, or stiff after a walk. Pain frequently presents as a change in behaviour rather than as obvious lameness.
Rebuilding it, 6 minutes a day, door open
The door stays open for the whole first week. Relaxation is trained as a behaviour in its own right, in short repeatable sets below the dog's threshold. A shut door puts most dogs over it.
Sit near the crate and toss 1 treat just inside the doorway. Let your dog go in, eat, and come straight out. Repeat 10 times without ever closing anything.
Now toss the treat to the back wall. Feed a second treat while your dog is still standing inside, then let them leave. 10 reps, then stop for the day.
The next day, feed your dog's whole dinner in the crate with the door open, and walk away while they eat.
Only once your dog goes in and lies down on their own do you touch the door. Then close it for 2 seconds and open it again.
If your dog will not come out of a session wanting more, the reps were too long. Short and dull beats long and tense every time.
What to stop
Stop pushing, lifting or luring your dog in and shutting the door behind them. Every repetition of that teaches that the doorway is a trap, and you undo a week of work in 30 seconds.
Stop using it as a consequence after something goes wrong in the house. A crate cannot be a place to relax and a place you get sent.
Safety note
Panic is different from protest. Drooling, bent bars, broken nails, injured gums, urinating or defecating in the crate, or barking that does not stop at all is panic. Stop crate work and speak to your veterinarian and a qualified behaviour professional. Gradual, sub-threshold departure practice is the core of separation-related behaviour work, and a panicking dog is above threshold.
You may not need a crate at all
A crate is one management tool, not a requirement. A puppy-gated kitchen with a bed in it does the same job for many adolescent dogs. That is a legitimate answer rather than a compromise.
Today's version, in one line: 10 treats tossed into a crate with the door tied open, then stop.