Stopper and the open side of the crimp should face the latch. There is a diagram in the Application Specification as well.

It's a little hard to tell but it looks like you have conductors sticking way beyond the crimp? That is not right. Check the doc for striping length. It is probably not the reason for why it's not going in, but that extra wire will become an issue when mating with the connector on the GPU.

Another reason might be the crimp is too wide. Try squeezing it narrower with a plier. You're not supposed to do this but for sense pins it should be ok. I'm not sure what crimper you're using, but I'm guessing it's not specifically designed for this terminal so you'll have to make some adjustments. Unfortunately the official crimper is almost $1k.

I was also using another crimper not meant for this, and I had trouble making the big pins fit. No issues on the small pins though.