After my horse jumps, he drags me after the landing, any tips to help him stop this ?

I recommend poles after the jump. It'll steal his focus away from his actions in order for him to get over them. If you'd like to go bigger, grid work would help as well, whether all one size, or increasing the size as you go.
Put the jump closer to the fence, loosen your rein and let him run into it a few times. If that doesn't work try having someone stand 6 strides out with a bucket of grain. If your horse is food driven that'll make them stop. Take the grain away after you've tried it a few times. Repeat until it sets in.
try stopping him right after the jump and making him back up straight
make him halt on a straight line after the jump if you can
Most likely you horse grabs the bit and runs so I would try a Waterford the are really good
Do grids and then ground poles to keep him focused
Put poles after the jump to make him pay attention
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