Look at the research done by psychotherapists in the 1970s, there is a web of connections between Alexander Shulgin, the Boston Group, and a few psychotherapists of the time before MDMA was banned. It was quite promising at the time, unfortunately the War on Drugs completely destroyed those advances for the past 40 years.

So the question is not so much "does it fix something?" as it's been already answered at the time, the question is more "how to be the most effective with this type of treatment" which more research is needed for. PTSD seems to be a prime candidate for the effects of MDMA, if you've ever taken MDMA recreationally you understand how the openness it enables to talk about your feelings could be therapeutically used, what's needed to be honed down is the method to do it clinically consistently.

It doesn’t, therapy does. When you take it suddenly - within an hour - you find yourself in a very different mindstate where you don’t feel shit, maybe for the first time in your life. This experience can shorten the time you need to process, it can make the therapy shorter. It’s not the drug doing its thing, it’s you and the therapist together doing the thing.