Does this happen with a particular airport/airfield? Did you trired to load into different airports/airfields?
I once had a similar issue where I was not able to load into two airports in a small region.
I can’t tell you how to solve it though, because for me it resolves itself after some time.
What I can tell you though: I had a addon airfield installed previousley in this region. I suspected that this airfield was the culprit, so I uninstalled it → it had the same effect as you are observing → none in this case, sim still crashed. After all worked again I reinstalled the addon airfield and it worked as it should.
These CTDs on loading can be quite difficult to figure out.