From the angle of the picture, it looks like you approach the dragon from above when you reach down to him. Any movement from above instinctively make dragons defensive. To them anything coming from above means a predator is coming to eat them. Try bringing your hand in from below and a foot or so away then hold your hand still. Don't try and pick up the dragon right now as he will only associate the hand and you as something rather unpleasant.
Being picked up the tail isn't a safe way to hold a dragon. It's better to bring your hand under the dragon and let him climb onto your hand and lift him that way. I wouldn't attempt to lift him at all till he calms down. There is just more chance of dropping him as you pick up a madly struggling dragon. I don't really agree with forcefully pushing their mouths closed.
You have to keep in mind the dragon has been moved from one place to another, somewhere were he was for well over a year (of not the full 2 years). It may take him longer toget used to his new home and owner.
Once he is used to having your hand in the cage, remove the glove and see how he reacts to it then. Then offer him some treats so he learns the hand offers tasty things. Once he is much calmer then try and pick him up and hold him, even if he struggles. Once he calms down, put him back into the cage. Every couple days, hold him longer after calming down before putting him back in the cage. This gets him to associate being calm in your hands is the best way to get put down. After a month or two you should see noticeable improvement, providing you keep at it a few times a day. Don't expect him to improve over night, or even in a week.
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PHLdyPayne