We often hear about problems with logging in to the Hosted Chef Manage interface. Most often, the issue will occur when trying to login with an email address, like "firstname.lastname@example.org" and especially after a password reset.
Inside the Hosted Chef system, you are only known as your username. I can see my username here https://www.chef.io/account/profile at the top in all uppercase after the "Signed in as:" label.
When resetting the password for your account at https://id.chef.io/id/password-reset/new, you will use the email address associated with your account. This will change the password for the username associated with that email address.
When logging in at https://manage.chef.io/login, you should only use the username that is associated with the email address you used above. Email addresses are not valid logins at this time. Your username will always consist of the valid characters shown below in the note.
You can see that email addresses are not valid logins by trying to create a new account at the Manage login screen. When you enter an email address in place of a username, Manage's validation will kick back and show that "@" is not one of the characters allowed in a valid username.
The text presented to highlight the validation failure is:
"Username can only contain lowercase letters, numbers, hyphens, and underscores"