If this is an example of the typical stopping, then I agree with everyone that you need to make the exercises more simple and inviting to this horse. Some horses need all the poles and some mental challenges. Your horse loses confidence and then so do you. He’s not one who can adapt to lack of accuracy super well, which is the only thing sort of less ammy friendly that I’m seeing. He did seem pretty game actually when you went back to the exercise and gave him a confident ride. But you need to set him up better for success from the start.
I’ve seen this a fair amount. For example a friend of mine was teaching her young horse to jump. He was generally pretty brave. But he was either dead quiet or had a ton of anxiety–not a lot in between those extremes. Her trainer was just working on some lines of poles, and he handled it great one direction, but the other direction, the first pole was set awkwardly coming out of the corner, so it was hard to ride the right track to get there comfortably. After a few mistakes, he started losing it. Some days later, rider tried working on the exercise herself and ran into a similar problem. I was there riding my horse at the time and suggested we move the first pole. And then when she did it off that direction, only do the first pole on a circle. Forget the rest of the related distances until he forgot about the previous ride and chilled out.
One might say, the horse needs to figure it out to be an amateur’s horse or a broke horse. Sure. But when they are learning and struggling, why invite a meltdown if it can be avoided just by building an exercise that the horse can be comfortable and confident with until they are used to those basics enough to be able to also think about harder questions? Some young horses do great doing lots of combinations. Would not be my choice for your horse in particular except for trotting in to a very inviting distance.
I had one young horse who in the beginning would over jump land 12 feet into a gymnastic, and so I had to set things long and then bring them in tighter as he figured it out. Other horses may need to start small and then expand out. And then there are some green horses who don’t have either of those issues.
If this kind of thing is happening regularly, you need a trainer who can recognize this and learn how to help your horse gain confidence and then progress as appropriate. If they can’t, then you need a new trainer.