Haven't seen this mentioned about Ancestry.com yet:
1. They time-out you pretty fast.
2. When I was seemingly "locked out" of my DNA results, I called them, and they said, they tried my account on with the MS Edge browser. I was using Chrome. I always get in with Edge, but not always with Chrome.
3. Make sure you link your DNA results with your account. Easy to forget.
4. Since I only use Ancestry for half a year, I'm not signed up right now, and a lot of stuff that I was able to see in the DNA section is now giving me error messages. Like sometimes, they won't even let me see my already starred and annotated matches!