I tried signing up the day it launched and ran into issues with 404s. After 3 or 4 days, I was finally able to create an account. When I went back the following day to login for the first time to choose a plan, I couldn't login.
I get a message saying my login credentials are incorrect. I hit the forgot password link and enter in my username. It finds my account and sends me a password reset email. I click on the link in the password reset email and it takes me back to healthcare.gov with an error message that my account can't be found, which obviously makes no sense because they just used my account to send me an email.
Live Chat has provided zero help, only stating that it's probably a performance issue and to try back later.
One odd thing is that the registration page says you a need a lower case and upper case character, a number and at least one symbol from a pre-defined set. To my knowledge, I didn't use an uppercase character, nor do I use one when do the password reset, which properly sends me an email. I feel like maybe the login portion is properly validating the username requirements, but the registration didn't which is what has left me in this mess.
I just signed up and had no problems.