Dog Nervous when training

[Gordon325]

I have a three year old male Jack Russell mix named Jax, he is very intelligent.
When we got him a year ago he knew no commands and was only partially house broken, now he is house broken and knows about 10 commands flawlessly... recently i decided to teach him how to close doors and cupboards.... I started by holding a sticky note on my finger and rewarding him when he touches it with his nose.... he was doing very good I began to use the command "door" and put the sticky note on the door and would rewarded for touching the sticky note on the door....

he did it a few times then would just sit there and stare at me like he was scared.... wagging his tail short and quick (nervously)... I just assumed he didnt catch on quite yet so i put it back on my finger and said door... and he continued to sit there nervously... I brought the sticky note closer to his face and he would VERY LIGHTLY touch it but would not move from his sit position if i moved it further away...

I have NO idea what is going on ... he usually learns VERY quick...and seemingly began to learn this one quickly... but after about 5 min of training he does the nervous sitting thing....

I do not get after him when he does it... i use positive reinforcement i try to get him excited and jumping around and he just goes right back to sitting when i try to get him going on the sticky note again